Unmanned aerial vehicle area surveying

ABSTRACT

Methods, systems and apparatus, including computer programs encoded on computer storage media for an unmanned aerial vehicle aerial survey. One of the methods includes receiving information specifying a location to be inspected by an unmanned aerial vehicle (UAV), the inspection including the UAV capturing images of the location. Information describing a boundary of the location to be inspected is obtained. Inspections to be assigned to the location are determined, with the inspection legs being parallel and separated by a particular width. A flight pattern is determined based on a minimum turning radius of the UAV, with the flight pattern specifying an order each inspection leg is to be navigated along, and a direction of the navigation.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference in their entirety under37 CFR 1.57.

BACKGROUND

Unmanned aerial vehicles (UAVs) can be navigated, for instance in aconsumer setting, by consumers according to manual inputs provided viacontrollers operated by the consumers. In commercial settings, a UAV canbe operated according to an autopilot executing on the UAV that followsa pre-programmed flight plan. For instance, the flight plan can includeone or more waypoints specified by Global Navigation Satellite System(GNSS) coordinates (e.g., GPS, GLONASS, BeiDou, Galileo, coordinates),and the autopilot can cause the UAV to navigate to each waypoint.

SUMMARY

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. A flight planning system can, with minimal userinput, determine a flight pattern for an unmanned aerial vehicle (UAV)to implement, such that the UAV can traverse an area to be inspectedaccording to constraints associated with the UAV. For instance, the UAV,such as a fixed-wing vehicle, can be constrained according to a minimumturning radius that the UAV can perform (e.g., the UAV can be limited toa maximum bank angle, and/or a maximum velocity). When inspecting anarea, such as a large agricultural area, mining area, and so on, theflight planning system can determine an optimal flight pattern for theUAV to follow such that the UAV can obtain sensor information (e.g.,capture images) of the area with a minimum amount of flight time orflight distance.

Additionally, the flight planning system can access weather information(e.g., weather prediction information) for an area that includes thatthe area to be inspected, and can modify a flight plan according toexpected wind conditions. Similarly, the flight planning system cangenerate multiple flight plans, and a UAV performing an inspection, oran operator located proximate to the UAV, can select between generatedflight plans according to actual wind conditions.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in systems, computer readable media,and methods that include the actions of determining a boundary for anarea to be inspected by an unmanned aerial vehicle (UAV); determining aflight pattern for the area, the flight pattern including a plurality ofinspection legs being substantially parallel to one another, andadjacent inspection legs being separated, by a particular width, whereinat least a first set of two adjacent inspection legs are to be traversedin the same direction by the UAV, wherein each inspection leg isassociated with the UAV performing an aerial inspection of the areaalong the inspection leg; and autonomously navigating the UAV accordingto the determined flight pattern, and obtaining sensor data of the areawhile the UAV navigates along each inspection leg.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in systems, computer readable media,and methods that include the actions of receiving information specifyinga location to be inspected by an unmanned aerial vehicle (UAV), theinspection comprising the UAV capturing images of the location;obtaining information describing a boundary of the location to beinspected; determining a plurality of inspection legs to be assigned tothe location, the inspection legs being parallel and adjacent inspectionlegs being separated, along a first dimension of the location, by aparticular width, wherein each inspection leg connects, along a seconddimension of the location, opposite portions of the boundary of thelocation, and wherein each inspection leg is associated with the UAVperforming an inspection of the location along the inspection leg;determining a flight pattern associated with navigating the inspectionlegs, wherein the flight pattern specifies a navigation order of eachinspection leg, and wherein the flight pattern is constrained by aminimum turning radius of the UAV; and generating, based on thedetermined flight pattern, a flight package to be provided to the UAV.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in systems, computer readable media,and methods that include the actions of displaying via a user interface,one or more images depicting a view of a location; determining a launchlocation for the UAV, the launch location having an associatedgeospatial location; determining a landing location for the UAV, thelanding location having an associated geospatial location; determining aflight path for the UAV comprising multiple legs to be flown by the UAVat a survey attitude, wherein the survey altitude is based on a coveragearea of one or more sensors used by the UAV for a survey.

The details of one or more embodiments of the subject matter of thisspecification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an unmanned aerial vehicle (UAV) performing aninspection of an area according to a first example flight plan.

FIG. 1B illustrates the UAV performing an inspection of the areaaccording to a second example flight plan.

FIG. 2A illustrates an example user interface for determining a geofenceboundary.

FIG. 2B illustrates an example of a geofence boundary associated with aflight pattern.

FIG. 2C illustrates an example user interface for determining alaunch/landing location.

FIG. 2D illustrates navigating from a launch location to an initial leg.

FIG. 2E illustrates an example user interface for determining a flightpattern to perform an inspection of a location.

FIG. 2F illustrates an example of an area to be inspected, with a firstdimension of the area being greater than a threshold distance.

FIG. 3 illustrates a block diagram of an example flight planning system.

FIG. 4 illustrates an example process of generating a flight package tobe provided to a UAV to perform an inspection of a location.

FIG. 5 illustrates an example process for determining a flight patternassociated with inspecting a location.

FIG. 6A illustrates an example of a radiator flight pattern.

FIG. 6B illustrates a situation in which a minimum turn radius of a UAVis equal to the width between legs.

FIG. 6C illustrates a leg index associated with a number of legs.

FIG. 6D illustrates traversal directions associated with legs.

FIGS. 6E-6F illustrate two examples transitions between example legs.

FIG. 6G illustrates an example inspection area.

FIG. 7 is a flowchart of an example process for a UAV modifying a flightplan according to wind affecting the UAV.

FIG. 8 illustrates a block diagram of an example Unmanned Aerial Vehicle(UAV) architecture.

DETAILED DESCRIPTION

A flight planning system (e.g., the flight planning system 300 describedbelow), can generate flight plans for an unmanned aerial vehicle (UAV)to implement, which enable the UAV to perform tasks including, forexample, inspections of areas (e.g., large areas, such as farms,forests, mining areas, large construction sites, and so on). In thisspecification, a flight plan includes all information sufficient toenable a UAV, optionally in concert with an operator located proximateto the UAV, to perform tasks, activate one or more sensors (e.g.,cameras, infra-red sensors, ultraviolet sensors, distance sensors suchas Lidar, Leddar, and so on), navigate to waypoints or along a flightpattern, and so on. As will be described, the UAV can activate sensors(e.g., obtain images) periodically according to distance traveled (e.g.,ground distance traveled based on GNSS information), periodicallyaccording to time, according to one or more triggers (e.g., an operatorcan trigger the UAV to capture one or more images), and so on. Theobtained images can be provided to an outside system (e.g., aphotogrammetry system) that can combine (e.g., stitch together) theimages, generate a 3D model, and so on.

The flight planning system can receive, or otherwise obtain, informationdescribing an area to be inspected, such as an address, GNSS coordinates(e.g., longitude/latitude), and so on, and, optionally along with userinput, can determine a flight pattern for the UAV to follow. In thisspecification a flight pattern is a real-world route the UAV is tofollow, and can include waypoints the UAV is to travel to, informationindicating locations, times, and or events, associated with the UAVexecuting turns, changing altitudes, hovering, performing actions (e.g.,capturing images), and so on. As an example, a flight pattern canindicate particular waypoints connected by lines, curves, and so on,that are sufficient to enable the UAV to navigate according to theflight pattern (e.g., a flight pattern as illustrated in FIGS. 1A-1B).

To determine the flight plan, the flight planning system can determinean efficient and economical flight pattern (e.g., minimizing flighttime, distance traveled, distance traveled that is not associated withthe inspection such as by making turns, re-traversing portions of thearea to be inspected, and so on), which as will be described, can bebased on configuration information of the UAV (e.g., a fixed-wing UAVcan be constrained to perform turns with a particular minimum turningradius, which can be a user-preference or based on capabilities of theUAV), information describing the area (e.g., property boundaryinformation), a desired level of detail to be captured in sensorinformation, and so on. In this specification, a level of detail isdescribed herein as a ground sampling distance, which indicates aminimum number of pixels/distance (e.g., pixels/meter), orpixels/distance², included in an image of a surface, object, orarbitrary real-world item.

The flight planning system can determine a flight pattern by dividingthe area to be inspected into parallel legs, with each leg separated ina same direction, from an adjacent leg, by a same width that is based ona ground sampling distance (e.g., a user selected ground samplingdistance). For instance, a high ground sampling distance (e.g., a highlevel of detail) can cause the UAV to fly at a lower altitude, such thatthe field of view of a camera utilized by the UAV will include less ofthe area being imaged, and thus more detail of the area. Therefore, thewidth between legs can be determined to be closer to allow for theentirety of the inspection area to be imaged. In this specification, aleg refers to a straight (e.g., substantially straight, such as within athreshold angle) section, or path, flown by a UAV within the borders ofa photosurvey planning polygon (e.g., a shape describing the area to beinspected), along which the UAV is intended to fly at a particularaltitude while the imaging payload (e.g., camera) is commanded, orotherwise instructed, to capture images at regularly spatially separatedintervals (e.g. every 5 m, which can be based on a ground distance, GNSScoordinates, and so on). A photo survey will typically be comprised ofseveral such legs parallel to one another. While the legs are ideallysubstantially parallel with one another, and at a similar distance,optionally there can be deviation.

Since the flight pattern of the UAV can be constrained, for instance bya minimum turning radius the UAV can perform, the flight planning systemcan determine an order that the UAV is to travel to each leg to ensurethat the UAV travels a minimum (e.g., within a threshold of a minimum)total distance while obtaining survey data (e.g., obtaining images). Forinstance, the UAV can begin the flight plan at a first leg (e.g., a topleg, such as at or near an extremity, border, of the area to beinspected), and after completing the first leg, the UAV can execute aturn according to its minimum turning radius. The flight planning systemcan determine that the second leg after completing the turn is aparticular number (e.g., 3 legs, and so on) below the first leg.Similarly, after the second leg is completed, the flight planning systemcan determine that the third leg is a particular number (e.g., 2 legs)above the second leg. The flight planning system can then determine thatthe fourth leg is a particular number (e.g., 3 legs) below the thirdleg, and so on until each leg has been assigned an order. In this way,the flight planning system can cause the UAV to skip legs whennavigating according to the determined order, based on capabilities(e.g., turning radius) of the UAV, optionally combined with weatherinformation (e.g., wind). An example of a flight pattern in accordancewith the above is illustrated in FIG. 6G. As will be described below,the flight planning system can ensure that legs are not re-traversed,that is legs are only navigated along once. Optionally, the flightplanning system can cause the UAV to navigate along each leg more thanonce, for instance navigating along each leg in a first direction, andthen in a second (e.g., opposite) direction.

Alternatively, the flight planning system can determine (e.g., based ona turning radius of the UAV, and a spacing between each leg) that eachsubsequent leg, according to the determined order, is the adjacent legalong a same direction, generating a “radiator” or “zig-zag” pattern,which is illustrated in FIGS. 1A-1B, and further described below.

In addition, the flight planning system can provide information to theUAV sufficient to enable the UAV to determine the flight plan (e.g.,flight pattern) while in flight. For instance, the UAV can receive,maintain, or optionally determined online, information identifying aminimum turning radius, and the width separation between legs, and candetermine an order to assign to each leg during flight. As will bedescribed, the UAV can monitor its direction, a current leg beingnavigated, and a total number of legs that have been navigated, and candetermine a next leg that is to be navigated, along with a direction ofthe navigation, while in flight. Since the UAV can store theabove-described values, and not receive a flight plan specificallyidentifying an order assigned to each leg, for long flights the amountof storage space required in the UAV can be reduced. Additionally,complexity associated with implementing the flight plan can be reduced,reducing potential errors through easily describing core values (e.g.,turning radius, width separation, and so on) which can be utilized bythe UAV.

Optionally, the flight planning system can obtain terrain informationand weather information (e.g., weather prediction information obtainedfrom an outside system), and can utilize the obtained information indetermining a flight plan. As an example of utilizing terraininformation, the flight planning system can determine a launch/landinglocation, and a flight pattern between the locations as described above,such that the UAV will not be within a threshold distance of terrain(e.g., the UAV will not be close to a hill) during the flight plan. Forinstance, a launch location can cause the UAV to take-off, and ascend toa particular altitude over a distance (e.g., a distance based, in part,on configuration information of the UAV such as power characteristics,wing characteristics, and so on). The flight planning system can ensurethat terrain, or other obstacles, will not be within a thresholddistance of the UAV during ascent.

As an example, the flight planning system can determine an expectedincrease in altitude per distance (e.g., a rate of ascent) as the UAVnavigates from the launch location, and can determine that as the UAVnavigates according to the flight pattern (e.g., ascends), an obstacle(e.g., a building or structure) will be within a threshold distance(e.g., threshold distance below the UAV) while the UAV ascends. In thisexample, the flight planning system can determine to move the launchlocation further away from the obstacle, such that the UAV has a greaterground distance to ascend, or the launch location can be moved laterallyaway from the obstacle. Similarly, as an example of utilizing weatherinformation, the flight planning system can determine that wind isexpected to affect the area to be inspected in a particular direction(e.g., west, east, south, north), and can determine a launch/landinglocation based on the wind direction and wind speed. For instance, theflight planning system can determine that, given the wind direction, aflight pattern from the launch location to the first leg of the area tobe inspected is to be in the direction of the wind. In this way, theflight planning system can ensure that the UAV is not launching with atail-wind when initially launching and climbing to a particular altitude(e.g., an altitude above which the UAV can safely travel and avoidobstacles such as power lines, trees, buildings, cell towers, machinery,and so on). The flight planning system can optionally determine multiplelaunch/landing locations, with each location being associated withparticular wind characteristics. For instance, as will be described in,at least, FIG. 2C, each launch location can enable a UAV to ascend(e.g., at a particular rate given the impact of wind velocity and winddirection on the UAV) a sufficient vertical distance at a particularground distance to be able to clear (e.g., be a threshold distanceabove) obstacles (e.g., as described above), and also to be able tonavigate to a flight pattern to inspect an area. An operator locatedproximate to the area to be inspected can obtain actual windcharacteristics, and the relevant determined flight plan can beutilized.

As will be described, as the UAV navigates according to the determinedflight plan, the UAV activates sensors (e.g., captures images), which asan example, can be activated periodically in distance (e.g., grounddistance). In this way, the UAV can obtain regularly spaced images ofthe area to be inspected. Since wind (e.g., wind moving greater than athreshold speed) can affect the UAV's ability to travel in asubstantially straight line, to ensure that the UAV follows the flightplan, the UAV (e.g., a fixed-wing aircraft) can bank, or crab, in adirection of the wind to counteract effects of the wind. For particularUAVs that do not have gimbals operable to independently maneuver acamera, when the UAV banks against the wind the camera will no longer bepointing directly down to the surface being imaged (e.g., the ground).Rather, the camera will be pointed slightly askance, which can affect afield of view of the camera, and thus can affect processing of theimages to obtain a combined (e.g., stitched together) image (e.g., usinga photogrammetry system or photogrammetry software). The UAV computersystem can record the orientation of the UAV, and may need to adjust theperiodicity (e.g., as described above) of the images obtained to accountfor the change in the field of view of the camera.

To address the effect of a cross-wind, the UAV may bank against the windto maintain the flight path track over a leg. In the case of afixed-wing UAV with a non-gimbled camera, banking the UAV may cause thecamera's field-of-view to be angled with respect to the flight path, andnot capture images as intended. The UAV may determine that an imageshould be captured and then temporarily level the UAV, and activate asensor (e.g., capture an image). Afterwards, the UAV can resume bankingand navigate back to the flight pattern (e.g., if the wind blew it offcourse) until a subsequent activation of the sensor. Similarly, the UAVcan ‘crab’ (e.g., point a nose of the UAV partially into a direction ofthe wind), such that the UAV's overall trajectory is along the flightpattern. Since this turning will also affect a field of view of thecamera, the UAV can temporarily point along the flight pattern,optionally modify functionality of a stability controller (e.g.,increase a derivative component) to increase responsiveness to wind, andactivate the sensor. Furthermore, after activating the sensor, andwithin a threshold distance prior to a next activation and a thresholddistance subsequent to the next activation, the UAV can determine anoptimal time to active the sensor. For instance, the UAV can determine(e.g., measure) a temporary lull in the wind, and activate the sensor.As the UAV navigates along the flight pattern, the UAV can determinewind characteristics of the wind affecting the UAV, and to determine theoptimal time to activate the sensor, the UAV can determine that apresent measure of the wind characteristics (e.g., wind speed) is withina threshold tolerance of previously measured “lulls” in the wind. Inthis way, the UAV can accurately determine when the wind is at itslowest.

The periodicity of the images taken may be variable and adjustedaccording to the bank or crab angle of the UAV. For example, based onthe desired ground sampling distance, the altitude and speed flown, thesensor triggering can be set at a particular rate or at particularlocations along the flight path of a leg. However, if during flight, theUAV encounters a cross-wind that causes the UAV to bank or crab tomaintain the path along the leg, the triggering of the sensor may beincreased to ensure survey coverage.

Various types of UAVs may be used to implement the inventions describedherein (for example, a fixed wing airplane, helicopter, a multi-rotorvehicle (e.g., a quad-copter in single propeller and coaxialconfigurations), a vertical take-off and landing vehicle, lighter thanair aircraft). A multi-rotor vehicle in a coaxial configuration may usethe same propeller pitch and diameter propellers, use different pitchand diameter propellers, or variable pitch propellers. In thisspecification, UAVs include drones, un-operated aerial vehicles,remotely operated aircraft, unmanned aircraft systems, any aircraftcovered under Circular 328 AN/190 classified by the International CivilAviation Organization, and so on. In addition, certain aspects of thedisclosure can be utilized with other types of unmanned vehicles (e.g.,wheeled, tracked, and/or water vehicles). Sensors, which are included inthe general term payload (e.g., any hardware, software, module, and soon, that is not critical to the flight operation of the UAV), caninclude any device that captures real-world information, includingcameras, radiation measuring instruments, distance detectors such asLidar, and so on.

FIG. 1A illustrates a UAV 2 performing an inspection of an area 12according to a first example flight plan (e.g., generated by a flightplanning system 300). The UAV 2 is inspecting an area 12, which in theexample, is an agricultural area. The UAV 2 can inspect the area 12 to,for instance, determine health of crops growing in the area 12,determine portions of the area 12 that do not have growing crops, and soon. As the UAV 2 navigates around the area 12, the UAV 2 captures sensordata, such as images, of the area 12 (e.g., for an outsidephotogrammetry system to combine, for instance in combination withlocation information of the UAV 2). Optionally, as the UAV 2 capturesimages, the UAV 2 can provide the captured images or sensor data to auser device for review by an operator located proximate to the area 2,(e.g., a ground control system 330 described below) in wirelesscommunication with the UAV 2, to combine the images as they arereceived.

The UAV 2 is navigating according to the first example flight plan,which specifies a particular flight pattern the UAV 2 is to follow. Asillustrated in FIG. 1A, the flight pattern includes parallel legs thatcause the UAV to navigate from a particular side of the area 12 to theopposite side of the area 12. For instance, a first leg 14 (e.g., aninitial leg flown by the UAV 2) is from a left side of the area 12 to aright side of the area 12. After the UAV 2 reaches the right side of thearea 12, the UAV 2 performs a turn towards the bottom of FIG. 1A, andnavigates along a second leg 18 from the right side of the area 12 tothe left side of the area 12. The first leg 14 and the second 18 areseparated by a particular width 16. Additionally, as described above,the first leg 14 connects to the second 18 via a curved segment thatcauses the UAV 2 to turn from navigating along leg 14 to navigatingalong leg 18.

As will be described, the width 16 can be determined (e.g., by theflight planning system 300) from a ground sampling distance that a user(e.g., a user of the flight planning system 300) indicates as beingacceptable. As described above, a ground sampling distance specifies athreshold number of pixels per distance to be included in imagescaptured by the UAV 2, and is therefore associated with a level ofdetail to be included in the images. To ensure that the UAV 2 capturesimages with at least the ground sampling distance, the UAV 2 can berequired to travel lower than a particular altitude, which can be basedon configuration information of the UAV 2. For example, a configurationof the UAV 2 can include the UAV 2 utilizing a particular camera (e.g.,sensor size, sensor resolution, focal length(s) of a lens, aperture(s)of the lens, and so on), which can affect the particular altitude. Forexample, a camera with a longer focal length and/or with greater sensorresolution, will be able to obtain images with at least the groundsampling distance at a greater altitude than a camera with a lower focallength and/or with a lesser sensor resolution.

To ensure that the entirety of the area 12 is included in images, thewidth 16 between the legs can be set (e.g., by the flight planningsystem 300) such that images captured when navigating adjacent legscovers the entirety of the area between each adjacent leg. Optionally,the width 16 can be modified such that images captured when navigatingadjacent legs includes overlap. For instance, when navigating the firstleg 14 the UAV 2 can capture an image at a particular distance from theleft of the area 12, and when navigating the second leg 18, the UAV 2can capture an image at the particular distance from the left of thearea. These two captured images can include overlap of a same portion ofthe area 12 that is between the first leg 14 and the second leg 18. Thisoverlap can be utilized by an outside system, such as a photogrammetrysystem, to combine (e.g., stitch together) captured images (e.g., thesystem can recognize shared features included in the overlap, helpingthe system to combine the images). Furthermore, and as will bedescribed, the overlap can be modified based on wind characteristicsaffecting the UAV 2. For instance, the overlap can be increased, andthus the width 16 decreased, if wind is causing the UAV 2 to bankagainst the wind. As described above, the banking against the wind cancause the camera to be angled such that less images of the area 12 alonga particular direction is included in captured images.

The first example flight plan includes parallel legs, adjacent to eachother according to the width 16, which are positioned from a top of thearea 12 to a bottom of the area 12. The first example flight plan can bedetermined (e.g., by the flight planning system 300) according to one ormore constraints, such as a geofence (e.g., a virtual perimeter orvolume that limits allowable locations of the UAV 2, which can depend ontime, for instance the geofence can be active for at particulartime(s)), wind directionality, and so on. Alternatively, a secondexample flight plan (e.g., illustrated in FIG. 1B, and described below),can include an overall shorter distance traveled, and can be preferablein some implementations. However, for areas 12 that are big (e.g., long,greater than a threshold distance) in a particular direction (e.g., arectangle that is of a length substantially greater than its width), thefirst example flight plan can, in some implementations, be preferable.That is, the first example flight plan can include legs along theshorter direction that are adjacent along the longer direction. As theUAV 2 navigates according to the first example flight plan, aftercompleting a threshold number of legs (e.g., 5 legs, 10 legs, and soon), the UAV 2 can continue the flight plan upon receiving informationfrom an operator that the images captured in the threshold number oflegs are acceptable. That is, the operator can utilize a user device(e.g., the ground control system 330 described below), to determine thateach captured image exceeds one or more quality thresholds (e.g., theimages are not blurry due to a shutter speed being too low, notoverexposed, out of focus, and so on), and that a combined (e.g.,stitched together) image is acceptable. The operator can then provideinformation to the UAV 2 indicating that the UAV 2 is to continue tosuccessive legs, and the UAV 2 can continue with the flight plan (e.g.,the UAV 2 can, in some implementations, otherwise circle until receivingthe information). Alternatively, the operator can indicate that the UAV2 is to navigate back to one or more legs to re-capture images.Similarly, instead of circling until receiving information, the UAV 2can immediately continue with successive legs, and return to a prior legto re-capture images upon receipt of information specifying the return.Additionally, by separating portions of the flight plan into a thresholdnumber of legs, areas of the overall area to be inspected can beprocessed (e.g., images can be stitched together, 3D models can begenerated), and an operator can quickly access the processed areas in afaster period of time.

FIG. 1B illustrates the UAV 2 performing an inspection of the area 12according to a second example flight plan (e.g., generated by a flightplanning system 300). As described above, the second example flightincludes legs (e.g., legs 20, 22) along a direction orthogonal to thelegs (e.g., legs 14, 18) described in FIG. 1A, which are separated by awidth 24 (e.g., the width can be substantially the same width 16 as inFIG. 1A). Since the second example flight plan includes less turns thanthe first example flight plan, in some implementations the secondexample flight plan can be preferable to the first example flight plan.However, as will be described, the second example flight plan can beinfeasible when wind characteristics, a geofence (e.g., a geofence basedon a property boundary of the area 12, which may not allow for the UAV 2to navigate according to the first example flight plan as the turns maybe outside of the property boundary) that limits locations of the UAV 2,and so on, are taken into account. Similarly, the first example flightplan can be infeasible for similar reasons, the description that followscan be attributable to the flight plan described in FIG. 1A also.

As an example of wind speed making a flight plan infeasible, when theUAV 2 is navigating along a leg capturing images, a camera beingutilized by the UAV 2 can be associated with a minimum frame rate (e.g.,rate at which images are captured). Thus, if the UAV 2 exceeds aparticular speed, the UAV 2 will be unable to capture images fast enoughto obtain images of the entirety of the area 12 at the ground samplingdistance (e.g., acceptable number of pixels/distance as described). Thatis, a location at which the UAV 2 is to capture an image will be passedbefore the camera is able to capture a new image, such that the imagewill be captured at a location further along the leg. If wind isaffecting the UAV 2, for instance by being in a same direction asalternate legs, the wind can cause the UAV 2 to exceed a speed at whichthe UAV 2 is able to periodically capture sufficient images of the area12. In such a situation, the flight plan can be modified to utilize thefirst example flight plan, such that the UAV 2 is always travelingperpendicular to the direction of the wind when navigating along eachleg (e.g., a tail wind will not propelling the UAV 2 forward at toogreat of velocity).

A user can utilize one or more user interfaces, generated by a system(e.g., the flight planning system 300), to determine a flight plan to beprovided to a UAV. FIGS. 2A-2F illustrate example user interfaces thatcan be utilized (e.g., by a user) to specify information associated witha flight plan. The user interfaces are examples of interactive userinterfaces, generated by a system (e.g., the flight planning system 300,or a presentation system in communication with the flight planningsystem 300) that can receive user interactions, access one or moredatabases, and update the user interfaces in response to received userinteractions. The user interfaces can be a document (e.g., aninteractive document such as a web page), presented on a user device(e.g., a computer, a laptop, a tablet, a smart phone, other mobiledevice, etc.) for presentation to a user.

FIG. 2A illustrates an example user interface 200 for determining ageofence boundary 204. The user interface 200 includes one or moreimages 202 (e.g., satellite images as depicted in FIG. 2A) of a locationentered by the user of the user interface 200. The images 202 includedin the user interface 200 can be interactive, and the user can zoom inand out of the image 202 to obtain a greater or smaller real-world area.For instance, the user can interact with a zoom control, or the user canutilize a touch screen to zoom in and out (e.g., the user can pinch tozoom). User interface 200 further includes a selectable option toinclude particular layers 206 in the user interface 200. For instance, a“geofence” layer has been selected, such that a geofence boundary 204 isincluded over the images 202. Additional layers are described below, andinclude a launch/land area, and a photosurvey area that specifies aflight pattern (e.g., as illustrated in FIGS. 1A-1B described above).

As illustrated in FIG. 2, the images 202 includes a highlighted areathat defines a geofence boundary 204 to be enforced by a UAV whenimplementing a flight plan. As described above, a geofence is atwo-dimensional or three-dimensional location-based boundary, whichlimits allowable locations of a UAV. Different types of geofences may beused by the UAV during flight operations. A geofence boundary can berepresented on the displayed images 202 map as polygonal shapes, forexample a circle, rectangle, sphere, cylinder, or other shape. Ageofence may also be time-based (four-dimensional) where the geofenceexists for a particular duration, for example, a number of hours ordays, or for a specific time period, for example, from 2:00 p.m. to 4p.m. occurring on certain days, or other periods of time. Athree-dimensional geofence may exist in a particular space above ground.A geofence may be represented by latitudinal and longitudinal connectedpoints, or other coordinate systems. A geofence may be created such thatthe geofence has dynamic aspects to it where the geofence may increaseor decrease in size based on various conditions. For UAV flightoperations, geofence structures can be received by a UAV (e.g., includedin a flight plan) and stored in non-volatile memory.

For both autonomous UAV flight operations, and manually controlledflight operations, the UAV would be limited to flight within a flightboundary geofence 204. If, for example, an operator of the UAV (e.g., anoperator located proximate to the UAV) in a manually controlled modeattempts to maneuver the UAV outside of the flight boundary geofence204, the UAV may detect a contingency condition (that is, the UAV isabout to fly outside of the geofence), and then automatically direct theUAV to return to a specified predetermined landing location.Furthermore, if the UAV is capable of hovering, such as a multi-rotorUAV, the UAV may be inhibited from moving across a flight boundarygeofence, or perimeter, of the geofence, and the UAV could be set tohover and not continue past the perimeter of the geofence.

A user can specify a geofence 204 for a UAV to enforce. For instance,the user can select portions of the images 202, such that the selectedportions define a polygon associated with the geofence. The user canfurther select a portion of the polygon, and drag it, or move it, toexpand or contract the polygon according to the selections.Additionally, the user interface 200 can enable the user to select aparticular corner of the images 202, and drag the geofence shape intoexistence by moving a finger or stylus on a touch sensitive screen ofthe user device.

Optionally, the flight planning system 300 can obtain propertyinformation associated with an input location, such as propertyboundaries, and automatically include a highlighted portion of theimages 802 as being a possible flight boundary geofence. The system candetermine that the entered location information describes a particularproperty (e.g., an open clearing that borders the road), and canhighlight the particular property. Optionally, the system can include abuffer from the property boundaries of the location to ensure that evenwith a strong gust of wind, the UAV will remain within the propertyboundaries. The property information used to create the flight boundarygeofence can be of various data types, for example, parcel polygons,vector, rasterized, shape files, or other data types. For the particularproperty, the flight planning system may create the flight boundarygeofence based on the property shape data. The various data types canhave geolocation and/or coordinate information, such aslatitudinal/longitudinal points for use in orienting and creating theflight boundary geofence. The geofence envelope may be identical inshape to the property boundary. Optionally, the boundary of the geofencemay be reduced in size, which can create a buffer zone. For example, theflight boundary geofence may be reduced in size by a set distance, forexample 5 meters, towards a centroid of the property. The buffer zonemay help avoid an unintentional flyover of an adjacent propertyboundary. Optionally, the flight planning system may display an areawith parcel polygonal data. An interface of the flight planning systemmay then receive a selection of one or more parcels. The flight planningsystem then can use the selections to create one or more jobs (e.g.,inspections), and multiple geofence envelopes. For the multiple parcels,the operator would go to each parcel property, and conduct multiplejobs.

The geofence boundary 204 can further be associated with a flightpattern the UAV is to utilize to capture images of the included location202. For instance, as described above with respect to FIGS. 1A-1B, theUAV can navigate along adjacent legs separated by a width, and captureimages of the location. Determining a flight pattern is described below,with respect to FIG. 2D. The geofence boundary 204 can be generated tospecify a buffer zone about the flight pattern, for instance thegeofence boundary 204 can encompass the flight pattern and optionallyinclude a threshold distance from the flight pattern.

An example of a geofence boundary associated with a flight pattern isillustrated in FIG. 2B. The illustration includes legs 210 that a UAV isto navigate along, separated by a same width (e.g., as described above).The geofence boundary is a first distance 214 above and below an initialleg and final leg, and a second distance 212 to the left and right ofthe legs. The first distance 214 and the second distance 212 can beassociated with a minimum turning radius of a UAV that is to beutilized. That is, when the UAV completes navigating along a leg, itexecutes a turn, and navigates to a different leg. The flight planningsystem can obtain configuration information of a UAV to be utilized, andcan determine a minimum turning radius of the UAV, such as a user setvalue based on the UAV, or a turning radius of the UAV such that the UAVcan be in control during a turn when wind, speed, and other factors, aretaken into account. The second distance 212 can then be set at, atleast, the minimum turning radius, such that when the UAV executes aturn it is contained within the geofence boundary. Similarly, the firstdistance 214 can be set at, at least, twice the minimum turning radius.As will be described below, with respect to FIGS. 2C-2D, for a UAV tonavigate to an initial leg (e.g., from a take-off location), the UAV mayhave to execute a loop near the initial leg to orient itself properly.This loop can therefore require that the UAV move in a circle, or twicethe minimum turning radius.

FIG. 2C illustrates an example user interface 200 for determining alaunch/landing location. As described above, the user interface 200includes selectable options associated with layers 206. In the exampleof FIG. 2C, a layer associated with a launch/landing location has beenselected, such that the user interface 200 has been updated to include alaunch (e.g., safe take-off) location 216 and a landing (e.g., safelanding) location 218.

To determine a launch location, as described above the flight planningsystem 300 can access terrain information, weather information, andoptionally images, or 3D models, generated from prior executed flightplans. For instance, the flight planning system 300 can store, orotherwise maintain, information determined from prior flight plansassociated with inspecting the location 202. The flight planning system300 can determine a launch location using the images or 3D models todetermine obstacles that are located near the inspection location 202.

Furthermore, the launch location 216 can be located such that the UAV isable to navigate to an initial leg of a flight pattern. As illustratedin FIG. 2D, a UAV 220 is navigating from a launch location along aflight pattern 222 to reach an initial leg 224. The flight patternincludes the UAV 220 executing a loop 226 to orient itself along adirection of the initial leg 224. The flight planning system 300 candetermine the launch location 216 to be located such that a UAV is ableto orient itself along the initial 224 without violating a geofenceboundary (e.g., as described above in FIG. 2A).

In addition to the flight planning system 300 determining launch andlanding locations, a user of the user interface 200 can select thelaunch location 216 and landing location 218. Optionally, the flightplanning system 300 can analyze the selected launch location 216 andlanding location 218 to determine whether they are suitable to beutilized. For instance, the flight planning system 300 can identifywhether obstacles, such as water (e.g., a puddle), are located at, orwithin a threshold distance of, the locations 216, 218. Furthermore, theflight planning system 300 can determine whether a UAV will be able tonavigate to an initial leg, and or whether the UAV will be able tosafely ascend to the particular altitude from the launch location 216without encountering obstacles. If the flight planning system 300determines that the selected locations will cause an issue with theflight plan (e.g., likely cause an issue), the flight planning system300 can present a notification indicating that the launch location 216or the landing location 218 is not suitable.

Optionally, the flight planning system 300 can obtain informationassociated with prior flight plans to inspect the location 202. Theflight planning system 300 can present prior launch and landinglocations (e.g., locations associated with successful flight plans), andoptionally other information associated with the prior flight plans. Forexample, operators or other personnel that were involved in the priorflight plans might have recorded text describing the flight plans andany potential issues with the flight plans or location 202. Forinstance, an operator may have specified that a launch location had tobe moved once he/she got to the location 202 due to a powerline, orguy-wire, or other obstruction, which is not visible in obtained imagesof the location 202. In this way, the user interface 200 can present oneor more of, a location that was initially assigned for the prior flightplan, the operator's text indicating that the location isn't suitable,and a final launch location selected by the operator.

FIG. 2E illustrates an example user interface 200 for determining aflight pattern to perform an inspection of a location 202. The flightpattern can be included in the user interface 200 upon receiving a userselection of a layer 206 associated with the flight pattern (e.g.,“Photosurvey area” as illustrated).

To determine the flight pattern, a user of the user interface 200 canspecify a boundary of the location 202 to be inspected. For instance,the user can select corners of a polygon that encompasses the location202, the user can sketch (e.g., using a finger or pen on a touchsensitive screen) the boundary, and so on. The flight planning system300 can then determine a width that is to be utilized between legs ofthe flight pattern. As described above, the width can be based on aground sampling distance (e.g., a user selected ground samplingdistance) that identifies an acceptable number of image pixels perdistance, and is therefore associated with a level of detail (e.g.,detail required by the user). Utilizing the width, the flight planningsystem 300 determines a number of parallel legs to be flown by a UAV,such that the UAV can capture images of the entirety of the location202.

As illustrated in FIG. 2E, the flight planning system 300 has determinedthat there are to be seven legs each separated by the determined width.In addition to the number of legs, the flight planning system 300determines an order that each leg is to be navigated along, which aswill be further described, can be based on a minimum turning radius of aUAV to be utilized. As will be described in FIG. 3, the flight planningsystem 300 can store configuration information, and other informationindicative of capabilities, of various UAVs. The flight planning system300 can present users with specific UAVs that will be available for useat a time of the inspection (e.g., the flight planning system 300 canstore information describing upcoming flight plans). A user can select aparticular UAV, and the flight planning system 300 can determine anorder associated with each leg based on a turning radius associated withthe selected UAV. For instance, a UAV can be unable to execute a turnafter navigating along an initial leg, such that after executing theturn, the UAV is then able to navigate along an adjacent leg. Instead,the flight planning system 300 can determine that the UAV is to skip oneor more adjacent legs, and navigate along a later leg. Once the laterleg is navigated, the flight planning system 300 can determine that theUAV is to travel back up in the direction of the initial leg. An exampleof a flight pattern that skips adjacent legs is described below, andillustrated in FIG. 6B. Optionally, the flight planning system 300 canidentify UAVs that can execute turns such that the UAVs can navigatealong successive adjacent legs, and can present information to the userindicating the UAVs. Determining an order associated with each leg isdescribed in more detail below, with respect to FIG. 5.

As described above, for a location 202 greater than a threshold size(e.g., greater than a threshold size along a same direction, such asgreater than a ½ a mile, 1 mile, 3/2 mile, 5 miles, and so on), theflight planning system 300 can determine sub-areas to be inspected thatare included in the location 202. For example, a polygonal shape, suchas a rectangle, can be separated into multiple polygons (e.g., multiplerectangles). The flight planning system 300 can separate the location202 into sub-areas, such that a UAV performing an inspection of thelocation 202 can navigate within the sub-areas, and not traverse theentirety of the threshold size in each leg.

Optionally, the flight planning system 300 can ensure that thelaunch/landing locations, flight pattern, and so on, are to beconstrained within the geofence boundary 204. That is, the system canlimit the extent to which the UAV executes a turn (e.g., limit themovement outside of an inspection area, for instance by immediatelyrequiring that the UAV execute a turn after completing a leg), and thusnavigates outside of the inspection area. The flight planning system 300can present a warning when a launch/landing location is selected outsideof the geofence, and can optionally block the location and/or recommendincreasing the geofence. Similarly, for a particular geofence envelope(e.g., one based on a property boundary), the system 300 can determinethat a particular UAV (e.g., model of UAV) does not have a minimumturning radius necessary to stay within the geofence. For instance, theUAV may not be able to turn sharply enough such that it can follow aflight pattern that stays within the geofence (e.g., upon completing aleg, the UAV may not be able to turn to a subsequent leg without exitingthe geofence). The system 300 can access information indicating UAVs(e.g., available UAVs) and recommend a UAV that conforms to a minimumturning radius. Optionally the system 300 can block a UAV from receivingthe flight plan, or the UAV can be set to not implement the flight plan.Optionally, the system 300 can recommend an increase to the geofence, orindicate that to stay within the geofence, the UAV will have to startturning prior to completing each leg (e.g., thus the sides may not beable to be imaged). Additionally, the system 300 may modify the flightpattern such that the UAV executes a turn prior to completing each leg,and then after completing each leg, the UAV navigates along the sides ofthe inspection area to capture images of the missed portions.

FIG. 2F illustrates an example of an area 240 to be inspected, with afirst dimension 242 of the area 240 being greater than a thresholddistance. As described above, with reference to FIGS. 1A-1B, the flightplanning system 300 can generate a flight pattern that includes adjacentlegs, with the legs being along the longest dimension (e.g., the firstdimension 242). Since the first dimension 242 in this example is greaterthan the threshold distance, a UAV navigating along each leg will spenda long amount of time navigating along each leg capturing images. If acamera utilized by the UAV malfunctions, or the images need to beotherwise retaken, the UAV can spend time navigating back to locationsat which the camera malfunctioned. Additionally, as described above, theUAV can provide captured images to a user device of an operator (e.g., aground control system) located proximate to the area 240. As the userdevice receives images, the user device can combine (e.g., stitchtogether) the images (e.g., using photogrammetry software). In this way,the user of the user device can monitor a progress of the flight plan,and obtain useful images while the UAV is in flight. However, forsituations in which the UAV navigates along a same direction for greaterthan a threshold distance, to combine captured images, the user devicewould, in some implementations, require images be captured from adjacentlegs. Therefore, the user can be required to wait longer while enoughimages are captured.

As illustrated in FIG. 2F, two example flight plans are included, witheach flight including the area 240 separated into sub-areas, and groupsof legs performed in each sub-area. Since the area 240 is separated intosub-areas, images captured in each sub-area can be processed (e.g., bythe user device), enabling blocks, or other polygonal shapes, to bequickly processed. Similarly, other polygonal shapes, including a squarewith each dimension being greater a threshold size, can be separatedinto sub-areas.

FIG. 3 illustrates a block diagram of an example flight planning system300. The various illustrated components (e.g., systems and elementsillustrated in FIG. 3) may communicate over wired and/or wirelesscommunication channels (e.g., networks, peripheral buses, etc.). Theflight planning system 300 can be a system of one or more computers, orsoftware executing on a system of one or more computers, which is incommunication with, or maintains, one or more databases (e.g., databases306-309), and in communication with one or more user devices (e.g., userdevices 310 and 330). The flight planning system 300 can be a system ofone or more processors, graphics processors, logic circuits, analogcircuits, associated volatile and/or non-volatile memory, associatedinput/output data ports, power ports, etc., and/or one or more softwareprocessing executing one or more processors or computers.

As described above, the flight planning system 300 can determine flightplans, including particular flight patterns for a UAV to follow, thatare associated with performing inspections of areas. The flight planningsystem 300 includes a flight plan determination engine 302 that cangenerate one or more user interfaces 316 (e.g., as described in FIGS.2A-2F) for presentation on a user device (e.g., User Device A 310), thatenable a user of the user device to specify information associated witha flight plan. The flight planning system 300 can be in communicationwith User Device A 310 over a wired or wireless connection (e.g., theInternet, a Local Area Network, a Wide Area Network, and so on), and theuser of the User Device A 310 can provide user input 340.

To describe one or more locations where the flight plan is to beconducted, a user interface 316 may be configured to receive, from theuser of User Device A 310, location information associated with theflight plan (e.g., an address of a home or property, GNSS coordinates,and so on), and the flight plan determination engine 302 can obtaininformation describing the location. For instance, the information caninclude property boundaries associated with an address (e.g., boundariesof a home, obtained from a database such as the Property/Map database306, or system, that stores or can access property boundaryinformation), obstacles associated with the location (e.g., nearbytrees, electrical towers, telephone poles) and/or other information.Additionally, the flight plan determination engine 302 can obtainimages, such as geo-rectified images (e.g., satellite images),associated with the entered location information. The flight plandetermination engine 302 can include some or all of the informationdescribing the location (e.g., the obtained images or boundaryinformation) in an interactive user interface 316 to be presented to theuser of User Device A 310.

As described above, the flight plan determination engine 302 can obtaininformation generated from prior flight plans, including detailed imagescaptured by a UAV performing a prior flight plan, a 3D model of an areathat was inspected, textual information specifying obstacles noticed byan operator positioned proximate to an inspection area, and so on. Theflight plan determination engine 302 can access a UAV Flight PlanInformation database 308 that stores information generated from priorflight plans, and can present information in the user interface 316specifying obstacles. For instance, the flight plan determination engine302 can identify, such as by highlighting, a particular area of theobtained images presented to the user that includes an obstacle.Additionally, the flight plan determination engine 302 can present awarning if the user places a take-off location, or landing location(e.g., as described above), at a location that will interfere with anobstacle (e.g., a UAV navigating from the take-off location, ordescending to the landing location, will be within a threshold distanceof an obstacle, or a particular type of obstacle).

The user of User Device A 310 may interact with user interfaces 316 todescribe a flight boundary geofence (as described above with respect toFIG. 2A) for a UAV to enforce. For instance, as described above, theflight plan determination engine 302 can provide images of a location,and a flight boundary geofence can be presented on the user interfacesover the images. The user interface 316 can provide functionality forthe user to select a presented shape (e.g., a polygon), and furtherfunctionality enabling the user to drag and/or drop the shape tosurround an area of interest in the received images that limitsallowable locations of a UAV to locations within the shape. Optionally,the user interface 316 may allow a user of User Device 310 to trace(e.g., using a finger or stylus) a particular shape onto a touch-screendisplay of the user device 310, and the flight plan determination engine302 can store information describing the trace as a flight boundarygeofence. That is, User Device 310 can provide information describingthe traced shape to the flight plan determination engine 302 (e.g.,coordinates associated with the images), and the flight plandetermination engine 302 can correlate the traced shape to locationinformation in the real-world as illustrated by the images (e.g., GNSScoordinates, such as GPS coordinates, that correspond to the tracedshape). Additionally, the geofence boundary can be described by one ormore boundaries of a polygon, or one or more points located on anoutside of the polygon, that are connected by lines, curves, and so on.The flight plan determination engine 302 can store the geofence boundaryaccording to the points and curve information (e.g., Bezier curves).

Additionally, as described above in FIG. 2A, the flight plandetermination engine 302 can determine a geofence boundary according tolocation that is to be inspected. For instance, the flight plandetermination engine 302 can generate a buffer around the location as ageofence boundary, such that a UAV flying a resulting flight pattern canbe located within the geofence when performing turns specified in theflight pattern. Since the turns can be dependent on a minimum turningradius of the UAV actually performing the flight pattern, the flightplan determination engine 302 can receive information identifying aparticular UAV that will be utilized and/or information identifying aminimum turning radius of a UAV to be utilized. If a minimum turningradius of not known, an operator positioned proximate to the location tobe inspected, can utilize a user device 330 (e.g., a ground controlsystem) to specify a minimum turning radius of the UAV that is beingutilized. Optionally, the flight plan determination engine 302 canutilize an average minimum turning radius, a worst-case minimum turningradius, and so on, as a constant when determining the buffer.

A user interface 316 can further enable the user to describe safelocations for a UAV to begin the flight plan (e.g., a take-off location)and end the flight plan (e.g., a landing location). As an example, theflight plan determination engine 302 can analyze the obtained imagesassociated with the entered location information, and identify ageometric center of a convex area (e.g., a biggest convex area) withinthe geofence boundary that does not include obstructions (e.g., trees,cell phone towers, powerlines, buildings), such as an open pasture.Similarly, the flight plan determination engine 302 can obtaintopological information associated with the entered locationinformation, and can detect substantially flat areas (e.g., areas withless than a threshold of variance in height). For instance, the flightplan determination engine 302 can determine that an open clearing (e.g.,an open clearing that is substantially flat) is a safe location for theUAV to take-off from, and can provide information recommending the openclearing in an interactive user interface 214 presented on the userdevice 212. Additionally, the flight plan determination engine 302 cananalyze the obtained images and locate physical features that are knownto generally be safe locations for take-off and landing. For example,the flight plan determination engine 302 can determine that a drivewayof a home associated with the flight plan is safe, and can select thedriveway as a safe take-off and landing location, or can recommend thedriveway as a safe take-off and landing location.

The flight planning system 300 may store, and maintain, configurationinformation associated with a UAV, for example in a UAV ConfigurationInformation database 309. Configuration information may includeconfiguration information of each UAV, such as a particular type of UAV(e.g., multi-rotor, quadcopter, fixed-wing), information describingsensors or other payload modules, gimbal information (e.g., whether theUAV includes gimbals that can control sensors), software information,information indicative of characteristics of the UAV (e.g., winginformation, motor information, and so on). The stored configurationinformation can be utilized by the flight plan determination engine 302to determine a minimum turning radius of a UAV. For instance, the flightplan determination engine 302 can determine a minimum turning radiusbased on particular characteristics of the UAV, such as a maximum, orotherwise safe (e.g., as indicated by a manufacturer, a user, which canbe based on weather information, and so on) bank angle based on wingcharacteristics, along with information describing motors and otherpower systems used by the UAV. For instance, the flight plandetermination engine 302 can determine the minimum turning radius basedon the maximum bank angle and a maximum speed that the UAV is to travelat (e.g., maximum safe speed, a speed constrained by a user,governmental entity, and so on). As described above, the minimum turningradius can be utilized when determining a geofence boundary, and aflight pattern for the UAV to follow.

The flight plan determination engine 302 can further determine, usingconfiguration information, particular UAVs that can implementfunctionality associated with a flight plan. For instance, theinspection of the location can be associated with determining whetherparticular types of hail damage are evident, or whether storm damage isevident, radiation is being included at the location, and so on. Theflight plan determination engine 302 can access configurationinformation of UAVs (e.g., UAVs available at a time associated with theflight plan), and can determine UAVs that include sensors, payloaddevices, and/or software such as computer vision algorithms, that canproperly effect the inspection. For instance, the flight plandetermination engine 302 can receive a time that the flight plan is tobe performed (e.g., a particular day, a particular time at a particularday, a range of times, and so on). The flight plan determination engine302 can then determine an availability of UAVs and/or operators at thereceived time(s) (e.g., the module 210 can obtain schedulinginformation). Additionally, the flight plan determination engine 302 canfilter the available UAVs according to determined configurationinformation (e.g., as described above). Optionally, the flight plandetermination engine 302 can access weather information associated withthe received time(s), and determine an optimal time or range of timesfor the job to be performed. For instance, a UAV that includesparticular sensors (e.g., electro-optic sensors) can obtain betterreal-world information at particular times of day (e.g., at noon on asunny day can provide better images by maximizing image contrast andminimizing the effects of shadows). As a further example, in the exampleof hail damage, the flight plan determination engine 302 can identify aUAV with, for instance heat and/or thermal imaging sensors, specificvisual classifiers that can discriminate hail damage from other types ofdamage, wind damage, rain damage, and so on. Similarly, as describedabove, flight plan determination engine 302 can determine one or moreUAVs with minimum turning radii that can enable the UAV to navigatealong successive legs of a flight pattern, instead of skipping legs aswill be described below and illustrated in FIG. 6B.

Using the above described geofence boundary, landing/launch location,and optionally a particular UAV selected for the flight plan, the flightplan determination engine 302 can determine a flight pattern thatenables a UAV to inspect the location. As described above, withreference to FIGS. 1A-1B, and 2E-2F, the flight plan determinationengine 302 determines a number of parallel legs spaced apart by aparticular width, that encompass the location to be inspected.

The particular width can be determined from a ground sampling distancethat the user of User Device A 310 specifies. As described above, aground sampling distance indicates, as one example, an acceptable numberof pixels/distance that are to be included in images captured by a UAV,and is therefore associated with a required level of detail of thecaptured images. The ground sampling distance can further specify amaximum altitude that the UAV can ascend to and still capture imagesaccording to the ground sampling distance. For instance, the maximumaltitude can be based on information associated with a camera to beutilized, such as a focal length of a lens, an aperture of a lens, asensor size and resolution, and so on. In addition to the maximumaltitude, the flight plan determination engine 302 can determine a safeminimum altitude, below which obstacles can be within a thresholddistance of the UAV.

To determine the particular width, the flight plan determination engine302 can ensure that a field of view of a camera will capture images fromadjacent legs that encompasses the area between the legs. For instance,if the ground sampling distance indicates a particular altitude the UAVis to fly at to capture images while navigating along each leg, theflight plan determination engine 302 can determine that a width betweeneach leg is set at a distance such that captured images, at theparticular altitude, will include the entirety of the area between eachleg. Optionally, and as will be described, the flight plan determinationengine 302 can further reduce the width, such that legs are spacedcloser together. The reduction in width can create an overlap areabetween each leg, such that images captured in adjacent legs willinclude a same overlap area between the legs. The overlap area can beuseful to ensure that the entirety of the location is imaged, forinstance if a UAV gets temporarily off course (e.g., due to wind, or atemporary autopilot malfunctioning, a contingency condition, and so on),a captured image could otherwise fail to include sufficient area. Theoverlap can act as a buffer against such situations.

The flight plan determination engine 302 further determines a number oflegs, a directionality of each leg, and an order associated with eachleg. As described above, the flight plan determination engine 302 canprefer that each leg be in a direction of a longest dimension of thelocation to be inspected (e.g., as illustrated in FIG. 1B). To determinea number of legs, the flight plan determination engine 302 can assign aninitial leg as being at an end of the location to be inspected, andassign successive legs spaced at the determined width apart until thelocation is encompassed. Optionally, the flight plan determinationengine 302 can determine a flight pattern from the take-off location tothe initial leg, which can include the flight pattern causing the UAV toorient itself near the initial leg (e.g., execute a loiter turn).Additionally, as will be described, the flight plan determination systemdetermines an order associated with each leg, which can be based on aminimum turning radius of a UAV and a width between each leg. Forinstance, if twice the minimum turning radius is less than the widthbetween legs, the flight pattern can be a zig-zag, radiator, and so on,pattern that enables the UAV to navigate to immediately adjacent legs.In another instance, if twice the minimum turning radius is greater thanor equal to the width, then the flight pattern can skip one or moreadjacent legs when traveling to a next leg in the determined order.

The flight plan determination engine 302 can further determineinformation specifying times, or locations, at which a UAV is to captureimages when navigating along the determined flight pattern. Forinstance, the UAV can capture images periodically (e.g., periodic inground distance traveled) while navigating along each leg, and notcapture images when executing turns. The flight plan determinationengine 302 can determine the periodic distance As described above, theUAV can provide captured images (e.g., over a wireless connection, suchas over 4G, LTE, Wi-Fi, BLUETOOTH, and so on) to a user device of anoperator located proximate to the location being inspected (e.g., to aground control system 330).

After determining the flight pattern, the flight plan determinationengine 302 can generate a flight package 304 to be provided to a UAV320, with the flight package 304 specifying information sufficient toimplement the determined flight plan. Optionally, the flight package 304can be formatted according to a particular UAV 320 (e.g., a particulartype), or to particular flight control systems, and/or softwareversions, included in the UAV 320. Optionally, the flight package 304can include a flight manifest file (e.g., an XML file) identifyingnecessary application and version information to conduct the flightplan. For instance, the UAV can be required to execute a particularapplication (e.g., “app” downloaded from an electronic applicationstore) that provides functionality necessary to conduct the flight plan.As illustrated, User Device B (e.g., a ground control system), such as atablet, laptop, wearable device, smart phone, or other user device thatincludes one or more processors, can receive the flight package 304(e.g., over a wired or wireless connection). The ground control system330 can be operated by an operator located proximate to a UAV performingthe flight plan.

The ground control system 330 can present one or more user interfacesthat describes the received flight package, such as user interfaces2A-2F, and can enable an operator to modify one or more aspects of theflight plan. For instance, upon arriving at the location to beinspected, the operator can determine that a launch location is to bemoved, or that a landing location is to be moved. Similarly, theoperator can obtain weather information for the location, such as a windspeed and direction, and provide the weather information to the groundcontrol system 330. The ground control system 330 can then modify one ormore aspects of the flight plan, for example reducing a width betweenadjacent legs (e.g., the reduction will create more overlap as describedabove, which can act as a buffer to guard against the negative effectsof wind). As another example, the ground control system 330 candetermine whether, given a wind speed and direction, the UAV cannavigate from the launch location safely to a particular altitude (e.g.,avoiding obstacles), and further whether the UAV can easily follow thedetermined flight pattern to orient itself at an initial leg of theflight pattern. If the wind speed, given the wind direction, is toogreat, the ground control system 330 can relocate the launch location.Similarly, the ground control system 330 can modify a landing locationbased on wind speed and direction. As described above, optionally theground control system 330 can ensure that the UAV is to be locatedwithin the geofence, and can optionally warn or block modifications tothe flight plan if they cause the UAV to navigate outside.

Optionally, given a particular wind speed and direction (e.g., asmeasured by the operator, or as obtained from one or more sensors, orobtained from an outside system over a wireless network, such as aweather system), the ground control system 330 can determine that theflight pattern is infeasible. As described above, the flight pattern canbe infeasible, when for instance, the wind can cause the UAV to travelfaster than a frame rate of a camera will allow. That is, the UAV cantravel too fast (e.g., a ground speed can be too great), such that amaximum frame rate of the camera will be unable to capture sufficientimages of the location. Thus, given the wind speed, and a minimum speedof the UAV, the ground control system 330 can determine that the maximumframe rate will be unable to match the determined periodic locations atwhich the UAV is to capture an image. As an example of wind affectingframe rate, if the commanded airspeed is 15 m/s (e.g., velocityindicated in the flight plan), and a downwind component is 5 m/s, thenthe downwind ground speed is 20 m/s. For a maximum frame rate of 1 fps,this survey is only feasible if the requested photo interval isperiodically set at 20 meters or more. The ground control system 330 canoptionally determine that the legs of the flight pattern are to berotated (e.g., rotated 90 degrees) if wind is affecting the UAV in anun-rotated direction, with additional legs added or subtracted to ensurethat the entirety of the location is imaged. Since the UAV, whennavigating along the rotated legs, will therefore not be in a samedirection as the direction of the wind, the UAV can travel at a speedthat enables it to capture images of the location.

The ground control system 330, or flight plan determination engine 302,can set a speed (e.g., a ground speed) at which the UAV is to travel at.For instance, a user can specify a speed, and/or the speed can be basedon configuration information of UAVs (e.g., capabilities of the UAV). Asdescribed above, a speed of the UAV can affect whether a camera cancapture images periodically according to distance traveled. Similarly,the speed can affect a shutter speed of a camera that is utilized, forinstance if the UAV is traveling at a particular speed, and the shutterspeed is set too low, the resulting images will be blurry. Since theshutter speed is affected by an aperture of a lens, an acceptable ISOlevel (e.g., a level at which noise will not cause the images to overlygrainy or lack detail), and an amount of light (e.g., sun light), theflight plan determination engine 302 can determines time at which theUAV is to perform the flight plan, such that light will be ample. Thatis, the flight plan determination engine 302 can prefer times away fromthe morning or evenings, and can access weather information to determineif weather will be cloudy or rainy. In this way, the flight plandetermination engine 302 can ensure that a shutter speed of a camerawill greater than a threshold (e.g., 1/125 second, 1/500 second, 1/1000second, and so on).

Optionally, the ground sampling distance can be modified during a flightof the UAV 320. For instance, as the UAV 320 is navigating along a legcapturing images, a wind in a direction of the UAV's travel 320 cancause the UAV 320 to move too fast to capture images (e.g., based on aframe rate of the camera as described above). The ground control system330 can receive information indicating that the UAV 320 is unable tocapture sufficient images (e.g., periodic images according to grounddistance traveled), and an operator of the ground control system 330 canmodify the ground sampling distance. The UAV 320 can then ascend to analtitude associated with the modified (e.g., reduced) ground samplingdistance, which can enable the UAV 320 to capture images at a slowerframe rate (e.g., since more area is included in each image due the UAV320 being located higher). Optionally, the UAV 320 can measure (e.g.,using one or more sensors) wind information, and can determine a minimaladjustment (e.g., modified by a buffer) to the ground sampling distancethat will enable the UAV 320 to capture sufficient images.

Additionally, a user of the flight planning system 300, or the operatorutilizing the ground control system 330, can specify a range ofacceptable ground sampling distances, and the UAV 320 can prefer themost detailed ground sampling distance. If the UAV 320 determines thatit is unable to capture sufficient images due to a tail-wind affectingits speed, the UAV 320 can ascend to a higher altitude until it is ableto capture sufficient images (e.g., images sufficient to include all ofthe location to be inspected).

The ground control system 330 can then provide the flight package 304,or an updated flight package 334 (e.g., modified as described above), tothe UAV 320. As the UAV 320 navigates according to the flight planindicated in the flight package 304, or updated flight package 334, theUAV can provide captured images to the ground control system 330 forpresentation. Additionally, as the UAV 320 conducts a flight plan, theground control system 330 can present a graphical representation of theprogress of the UAV. For instance, the user device can present images(e.g., satellite images) of the survey area along with a representationof the flight pattern the UAV 1 is to follow. As an example, therepresentation of the flight pattern can include legs connected byturns, with an order that each leg is to be navigated to, included inthe representation. The UAV 320 can provide geospatial locationinformation to the ground control system 330, and the ground controlsystem 330 can update a representation of the UAV 320 as it travels.Optionally, as the UAV 320 travels and captures sensor information(e.g., digital images), the ground control system 330 can include abounding quadrilateral, or other shape, around a representation of theUAV 320, which represents a field of view being captured by the UAV 320in sensor information (e.g., digital images), with for example, thefield of view being an area of the property included in the sensorinformation (e.g., based on capabilities of the camera, such as focallength, sensor resolution and size, lens aperture, and so on). Forinstance, a displayed representation of the UAV 320 traveling mayinclude a quadrilateral surrounding the representation. Thequadrilateral tracks the movement of the UAV 320, and may change shapesas the UAV 320 shifts (e.g., roll, yaw, pitch axes). The shape shows thesensor field of view for the area of the ground the sensor would cover.The quadrilateral can be determined from a determined field of view of asensor (e.g., camera) with respect to the UAV's 320 position (e.g.,height, latitude and longitude) and attitude information. The field ofview can be toggled on and off by the operator of the user device, andoptionally each quadrilateral captured by the UAV's 320 camera can behighlighted, colored, shaded, and so on, to indicate that the portion ofthe property has been captured in sensor information (e.g., digitalimages). In this way, the operator can monitor the progress of the UAV320, and ensure that the entirety of survey area is captured in images.

Although in one embodiment of the invention, the flight planning system300 may be primarily used to create and transmit a flight package to aUAV or ground control system, the UAV or ground control system caninitiate the request for a flight package from the flight planningsystem 200. An operator may take the UAV or ground control system to aproperty location (e.g., a location to be inspected). The UAV or groundcontrol system may then request a flight package, or an updated flightpackage using its current position. For example, the UAV or groundcontrol system can determine its geospatial position via a GNSS receiver(using GPS, GLONASS, Galileo, or Beidou system). The UAV or groundcontrol system can then transmit its location information to the flightplanning, along with other identifying information about the requestingdevice, such as its UID, or MAC address, etc. The flight planning system300 can then receive the request, and determine if an updated or changedflight package exists by comparing the device identifier a databasestoring the new or updated flight package information. If a new orupdated flight package exists, then the flight package can betransmitted from the flight planning system 300, and received by the UAVor ground control system. A confirmation acknowledging receipt of theflight package may then be transmitted from the UAV or ground controlsystem to the flight planning system 300. The flight planning system 300can then update a database specifying that the particular flight packagehas received. Moreover, the UAV or ground control system can supply theproperty location, and a new job request (e.g., new inspection) can besent to the flight planning system. The flight planning system 300 maythen create a new flight package for the UAV or ground control system.

Furthermore, as the UAV 320 navigates according to the flight plan, theUAV 320 can modify particulars of its movements based on wind affectingthe UAV 320. For instance, the UAV 320 can bank against the wind,causing the UAV to rotate about one or more axes (e.g., a roll axis). Ingeneral, for UAVs that do not include gimbals that can control attitudeinformation of a camera, the UAV 320 banking will cause the camera toalso rotate about the one or more axes. A field of view of the cameracan be modified in accordance with the rotation, such that the field ofview will not be directly of the surface beneath the UAV 320. To counterthe effects of the wind, the UAV 320 can temporarily return the UAV 320to a righted position, capture an image, and then resume banking againstthe wind. In another instance, the UAV 320 can crab as it navigates,such that a nose of the UAV 320 is pointed partially into the directionof the wind. Similar to banking, the UAV 320 can temporarily orientitself with a nose pointed along the direction of the leg, capture animage, and resume crabbing. Additionally, the UAV 320 can modify aflight pattern (e.g., the ground control system 330 can receive themodification and an operator can approve or deny), or the ground controlsystem 330 can modify the flight pattern based on determined windconditions. For instance, the width between legs can be decreaseddepending on a speed and directionality of the wind, such that more legsare to be navigated along. Since the width can be decreased, an orderthat each leg is assigned can be further modified, as the minimumturning radius of the UAV 320 can be too high to allow for the UAV 320to navigate to successive adjacent legs.

FIG. 4 illustrates an example process 400 of generating a flight packageto be provided to an unmanned aerial vehicle (UAV) to perform aninspection of a location (e.g., also described as an area). Forconvenience, the process 400 will be described as being performed by asystem of one or more computers (e.g., the flight planning system 300).

As described above, the system determines a flight package thatindicates a flight plan associated with a UAV performing an inspectionof a location (e.g., an agricultural area, a farm, a mining operation, ahouse tract, or any arbitrary area). As illustrated in FIGS. 1A-1B, theflight plan includes a flight pattern of parallel legs separated by aparticular width (e.g., a zig-zag pattern, a radiator pattern, and soon).

The system determines a width to assign between adjacent legs (block402). As described above, the system can obtain, or receive (e.g., froma user), information indicating a ground sampling distance that isacceptable for the flight plan. The system can determine a width basedon the ground sampling distance, and configuration information of a UAVincluding a camera, such as a focal length of the camera, a resolutionof a sensor, and so on. As described above, with respect to FIG. 3, thewidth can be a maximum distance that enables a UAV to capture images ofthe entirety of an area between each adjacent leg. Furthermore, thewidth can be shorter such that images captured while navigating adjacentlegs will include an overlap area that is imaged. This overlap area canbe utilized (e.g., by a photogrammetry system, or photogrammetrysoftware) to combine the images (e.g., stitch together images).

The system determines a flight plan geofence (block 404). The geofenceis determined based on (1) property information associated with alocation to be inspected, and/or (2) a buffer surrounding the area to beinspected. For example, as illustrated in FIG. 2B, a buffer surroundinga location to be inspected can be designated as a geofence (e.g., basedon a turning radius of a UAV, as described above). Optionally, thebuffer can represent a minimum geofence, such that if a propertyboundary is less than the buffer zone, the flight plan can, in someimplementations, not be performed as the UAV may travel across aproperty boundary into a neighboring property during the inspection. Todetermine the buffer, the system can obtain information describing thelocation to be inspected (e.g., from a property database, or a user candescribe the boundaries of the location using one or more user interfaceas described above).

The system generates a flight pattern for a UAV to implement (block406). As will be described in more detail, with respect to FIG. 5, thesystem utilizes the determined width and geofence to assign parallellegs to which the UAV is to navigate along, with an associated order anddirection assigned to each leg.

The system generates a flight package for implementation by a UAV (block408). As described above, with respect to FIG. 3, the system generates aflight package that is sufficient to enable the UAV to perform theinspection (e.g., in concert with an operator utilizing a ground controlsystem).

The system optionally obtains weather information associated with thelocation, and determines one or more alternate flight plans (block 410).As described above, weather, for instance, wind, can affect an abilityof a UAV to maintain a straight flight pattern, and additionally toexecute a turn. To counteract the effects of wind, the system canoptionally generate one or more alternative flight plans that can beutilized upon an operator arriving at the location and determiningactual wind conditions.

For instance, a turn that causes the UAV to move from a due eastdirection, along a southerly direction during the turn, and ending at awest direction, can be negatively affected by strong wind in thesouthern direction. The UAV will be pushed further south than a flightplan may have anticipated, which can cause the UAV to have to skip a legit would otherwise be able to navigate along absent wind. Therefore, thesystem can access weather information for the location, such as weatherprediction information, and weather information experienced in priorflight plans to inspect the location. As an example, a particularlocation can be known to generally be windy along a same direction at aparticular time of day. The system can generate an alternative flightplan, or optionally incorporate the weather information when firstgenerating a flight plan, that can take the wind into account.

An alternate flight plan can have a modified width between legs (e.g., areduction in width), such that the UAV may have to skip legs afterexecuting turns (e.g., due to a minimum turning radius), and return tothe skipped legs later in the flight plan. An example of skipping legsis described below, and illustrated in FIG. 6B. As described above, thereduction in width can account for the UAV having to bank against thewind or crab in a direction of the wind, which can affect a field ofview of a camera of the UAV.

Similarly, one or more alternate flight plans can include the legs beingrotated by a particular degree (e.g., 90 degrees), such that the windwill affect the UAV differently when navigating along each leg or whenexecuting turns. For example, as described above, wind can cause the UAVto travel further when executing a turn, causing the UAV unable tonavigate to a next ordered leg in the flight plan. An alternate flightplan can rotate the legs, such that the wind can cause the UAV to movefaster when navigating along a direction of the rotated leg, but causethe UAV to no longer travel too far when executing a turn.

In addition to modifying flight plans by modifying particular flightpatterns, the system can determine flight plans that include differentlaunch and landing locations. For example, if wind is in a direction ofthe UAV launching, the UAV may be unable to follow a flight pattern toreach an initial leg. For instance, the UAV may be unable to climb highenough in a distance specified in the flight pattern, due to the windpropelling it forward. Therefore, the system can determine alternatelaunch and landing locations that are associated with different windspeeds and directionalities.

FIG. 5 illustrates an example process 500 for determining a flightpattern associated with inspecting a location. For convenience, theprocess 500 will be described as being performed by a system of one ormore computers (e.g., the flight planning system 300).

The system determines a number of legs to assign to the location to beinspected (block 502). The system obtains information describing thelocation to be inspected, and based on the determined width between legs(e.g., described above with respect to FIG. 4), the system determines anumber of legs, spaced apart according to the width, that will enable aUAV to obtain images of the entirety of the location. Optionally, theinitial leg can be located at a boundary of the location, and legs canbe assigned towards an opposite boundary of the location. In someimplementations, the final leg may be located at the opposite boundary,or can be located a threshold distance from the boundary within thelocation, or located a threshold distance from the boundary outside thelocation. That is, depending on a shape of the location (e.g.,particular polygonal shape), to capture images of the location, the lastleg may be located within the location, on a boundary of the location,or outside the location (e.g., within the determined geofence).

The system determines a direction along a same axis that each leg is tobe navigated (block 504). As described above, the system can orient legsto be along a longest dimension of the location. For instance, asillustrated in FIG. 1B, the legs assigned to the location 10 areoriented from a top of the page to a bottom of the page. In this way,the system can minimize (e.g., substantially, such as within athreshold) a number of turns that the UAV has to make, and can thusensure that the UAV is spending more flight time capturing images.

The system determines an order and direction that each leg is to benavigated (block 506). Once the number of legs are determined andoriented, the system determines a flight pattern through the legs suchthat each leg is navigated along.

To initially reach a leg (e.g., an initial leg at a boundary of thelocation), the flight pattern can include a spiral ascent/descent beingperformed to a loiter circle that is aligned such that its exit bearingplaces the UAV on the initial leg of the survey. If the aircraft is notalready on the circle at maneuver initiation, the behavior is similar tothat of a flight circle maneuver: the circle will be intercepted at apoint of tangency from the aircraft's starting location. Like a flightcircle maneuver, the vehicle will climb or descend enroute towards thestarting rally (e.g., an enroute spiral). This initial flight pattern toreach the initial leg is described above, and illustrated in FIG. 2D.

The order and direction that each leg (e.g., subsequent to the initialleg) is based on the minimum turning radius of the UAV. As describedabove, the minimum turning radius is bounded by the commanded airspeedof the maneuver. This allows for a minimum turn radius to be chosenbased on the given desired airspeed and the maximum bank angle of theaircraft. Once the minimum turning radius is determined, the systemdetermines whether the minimum turning radius is less than twice thedetermined width, and if so, the flight pattern can a radiator pattern,such that the UAV can navigate to adjacent legs.

FIG. 6A illustrates an example of a radiator flight pattern. Asillustrated, a UAV 602 is navigating according to a flight pattern, inwhich each successive adjacent leg is navigated long after executing aturn 606. For instance, a first leg 604 is navigated along, a turn 606is executed, and a second leg 608, subsequent to the first leg 604, isnavigated along in an opposite direction.

When the twice the minimum turning radius (r) is greater than or equalto the determined width (w), 2*r>=w, the system clusters groups of legstogether, which is the more general case and described below withrespect to FIG. 6B. As illustrated in FIG. 6B the turn radius may be toolarge to allow a ‘radiator’ pattern (e.g., as illustrated in FIG. 6A).In this more general case, legs are initially skipped and then returnedto. FIG. 6B illustrates a situation in which the minimum turn radius isequal to the spacing (e.g., width) between survey (e.g., inspection)legs, and the UAV 612 skips two legs at a time, returning to fly thetopmost un-skipped leg. For instance, as illustrated in FIG. 6B, the UAV612 navigates along an initial leg 614, and upon completing the initialleg 614, executes a turn and skips two legs, and navigates in theopposite direction along leg 616. Once leg 616 is completed, the UAV 612executes a turn and moves back up by skipping a leg, and navigates alongleg 618. This skipping process repeats until all legs have beennavigated along.

In general, a process to determine an order and direction associatedwith each leg can be described, as follows.

As described above, a total number of legs ‘N’ can be determined.Referring to FIG. 6C, leg index iε{0, 1, 2, . . . , N−1} (a.k.a.‘index’): The first leg corresponds to i=0, the next nearest legcorresponds to i=1, and so forth. Note that since the leg index in theexample of FIG. 6C is zero-based, and the final leg in the survey is, insome examples, labeled i=N−1.

Leg pass number k ε{0, 1, 2, . . . N−1}: This value indexes the flightorder of the legs, with the first leg flown being k=0. For eachsubsequent leg, this value can be increased by one, thus tracking aquantity of legs that have been navigated.

Minimum vehicle turn radius R>0: This is the minimum turning radius, asdescribed above.

Minimum maneuver turn radius r≧R: The photo survey guidance method maynot command the vehicle to make turns that are smaller than this radius.Note that this value is maneuver specific and distinct from the vehicleminimum turn radius R; photo surveys must have r≧R.

Traversal index T(k) εi{0, 1, 2, . . . N−1}, that is T(k)=i. Thetraversal index indicates which order of a leg (e.g., k) is associatedwith each leg index (e.g., i). The first leg to be traversed is T(0)=0(i.e. the topmost leg); T(k) for m>0 depends on r and w, as prescribedby the method given below.

Referring to FIG. 6D, Traversal direction D(k)ε{−1, 1} (aka‘direction’): D(k)=1 can be defined, in some implementations, to be anindex k that is traversed in the same direction as the first (e.g.,initial) leg. Thus D(0)=1, since 0 corresponds to the initial leg in theorder. Legs flown in the opposite direction can have a direction of −1.In some implementations, the process can guarantee that D(k+1)=−D(k),such that the direction reverses with each traversal.

Leg exit direction X(k) ε{−1, 0, 1}: X(k)=1 can also be defined, in someimplementations, to mean that leg k will be exited via a right turn, andX(k)=−1 to mean it will be exited via a left turn. X(k)=0 indicates thata leg will be exited without a turn; this may happens on a final leg ofthe survey.

Leg entry direction E(k) ε{−1, 1}: E(k)=1 can be defined to mean, insome implementations, that leg k will be entered via a right turn, andE(k)=−1 to mean it will be entered via a left turn. Note that byconvention E(0)=1; that is, the topmost leg is entered via a right handturn (part of the starting rally); this keeps the starting rally circlewithin the survey area.

Referring to FIGS. 6E-6F, the figures illustrate E(k) and X(k) for twoexample transitions between legs k and k+1. Note that the values of E(k)and X(k) govern the ‘footprint’ of the maneuver when transitioningbetween legs and can be used to generate a more accurate buffer zone.

Optionally, E(k)=X(k−1); for a particular transition from one leg to thenext, the aircraft may execute turns in one direction.

Leg Traversal Order. Given that r (e.g., minimum maneuver turn radius,such as user set value, as described above), w (e.g., width betweenlegs), N (e.g., number of legs), are fixed throughout the flightpattern, the value for any k, of T(k), D(k), X(k−1) and E(k), given thevalues of T(k−1) and D(k−1), can be determined.

The system can compute T(k), D(k), X(k−1) and E(k), and also values forkε{0, 1, 2, . . . N−1} (e.g., the whole survey). Optionally, D(k) mayalternate between 1 and −1.

Optionally, to determine an order associated with each leg, the systemdetermines whether k_(current)≧i_(current)+1, and if so, the subsequentleg to be navigated along is a first number of legs subsequent to theinstant leg (e.g., i, as described above, represents a label associatedwith each leg, and i_(current) represents the instant leg), where thefirst number of legs is equal to ceiling

$\left( {2*\frac{r}{w}} \right) + 1.$

That is, for k+1, if the above determination is true, then

$i_{subsequent} = {i_{current} + {{ceiling}\mspace{14mu} \left( {2*\frac{r}{w}} \right)} + 1.}$

If the opposite, k<i_current+1 is true, then the subsequent leg to benavigated along is a second number of legs prior to the instant leg,where the second number of legs is equal to ceiling

$\left( {2*\frac{r}{w}} \right).$

That is, for k+1, if the above determination is true, then

$i_{subsequent} = {i_{current} - {{ceiling}\mspace{14mu} {\left( {2*\frac{r}{w}} \right).}}}$

In the above described optional determination of order, when ceiling

${\left( {2*\frac{r}{w}} \right) = 2},$

the UAV would navigate along a first leg, and skip 3 legs down, thenmove two legs back up, and repeat. Note that the UAV would, afternavigating along 5 legs (e.g., k>5), repeat the same navigation, exceptthe directionality would be reversed with respect to the priornavigation of 5 legs. An example of this periodicity is graphicallyillustrated with respect to FIG. 6G, and described below. Theperiodicity depends on the value of ceiling

$\left( {2*\frac{r}{w}} \right),$

for instance if ceiling

${\left( {2*\frac{r}{w}} \right) = 3},$

the periodicity would be 7, and so on. In general, the periodicity canbe represented as being equal to 2*ceiling

$\left( {2*\frac{r}{w}} \right) + 1.$

As described above, the UAV may determine this order while onlinethrough monitoring of the above-described variables.

In some implementations, and as an example, the system can determine anumber of legs to skip along a same direction after completing aparticular leg. That is, the system can determine that a subsequent legto be inspected, in a determined order, is (y=floor(2*r/w)+1) legsfurther than a present leg being inspected, with floor(2*r/w) equalingthe minimum number of legs that have to be skipped based on the turningradius. For instance, as illustrated in example FIG. 6B, in someimplementations, r can equal w (e.g., in some implementations r>=w),such that y would be determined as being 2. Therefore, after completingan inspection of a particular leg, the UAV would have to navigate to aminimum of a second leg after the particular leg (e.g., the UAV skips atleast one leg). However, as the UAV navigates from a top leg (e.g., asillustrated in FIG. 6B), the system can determine that the UAV shouldskip 2 legs when navigating towards the end of the area to a subsequentleg, and then skip 1 leg when navigating towards the top of the area toinspect a skipped leg. That is, since the UAV has to skip at least oneleg, the flight pattern causes the UAV to skip two legs when navigatingdownwards, and skip one leg when navigating upwards.

In some implementations, groups (e.g., clusters) of adjacent legs can bedetermined, with each group being associated with the UAV navigatingalong a same direction. For instance, as illustrated in FIG. 6B, thefirst three adjacent legs are navigated in a same direction (e.g.,direction ‘1’), while the next three adjacent legs are navigated in anopposite direction (e.g., direction ‘−1’). To determine a number ofadjacent legs that are to be grouped according to direction, the systemcan utilize the y=floor(2*r/w)+1 formula described above. For instance,in FIG. 6B, this formula can, as described above, be equivalent to 2.This value of 2 can represent a number of legs to be grouped together,in addition to the base case in which each group includes a single leg(e.g., as in FIG. 6A, subsequent legs switch order). Therefore, thevalue of 2 can be added to the base case of a single leg, and asillustrated, 3 adjacent legs can be grouped together. Therefore, thesystem can determine the flight pattern to start at the initial leg in afirst grouping (e.g., a grouping with direction ‘1’), and move to aninitial leg in a second grouping with direction ‘−1’ (e.g., by skippingtwo legs in a downward direction after the initial leg). After, theflight pattern can move to a subsequent leg in the first grouping (e.g.,the UAV can move upwards by skipping one leg), and then a subsequent legin the second groping (e.g., the UAV can skip two legs in a downwarddirection), and so on.

Turn Radius Less Than, To ½ Transect (2*r<w). Referring to FIG. 6A, inthis case, 2*r/w<1, so ceiling(2*r/w)=1, and so the traversal order willbe identical to the transect numbering and the vehicle will describe a‘radiator’ style ground track. In this case T(k)=m and D(k)=(−1)̂m, i.e.T(0)=0, D(0)=1, T(1)=1.

Turn Radius greater than or equal to ½ Transect (2*r>=w). Referring toFIG. 6B, in this case the 2nd leg to be traversed will be the fourth legfrom the top of the survey (T(1)=3, ‘skipping’ 2 transects), from rightto left (D(1)=−1), and the aircraft's 3rd traversed leg will be thesecond from the top (T(2)=1, covering the first ‘skipped’ transect),from left to right (D(3)=1). The 4th traversed leg is then the 5th legfrom the top of the survey, followed by the 5th traversed leg being the3rd from the top (covering the 2nd and last ‘skipped’ leg). At thispoint the pattern will recur, except flipped: The 6th leg to betraversed will be the sixth from the top (T(5)=5) and will be from rightto left (D(4)=−1).

As described above, an order can be assigned to each leg, along with adirection. In general, the description above has described a location tobe inspected as rectangular, however the shape of the location canaffect the order and direction of each leg. For example, returning toFIG. 6D, the UAV 632 is illustrated navigating from a third ordered leg642 (e.g., T(2) in the parlance described above). The UAV 632 began atan initial leg 634, executed a turn 636, and skipped the third leg 642,to navigate along a second leg 638. The UAV 632 was unable to execute aturn sharp enough after the initial leg 634 to navigate along theadjacent leg 642, and therefore had skipped the adjacent leg 642 tonavigate along leg 638. However, as illustrated, after navigating alongleg 638, the UAV executes a turn 640, and navigates along the adjacentleg 642 instead of skipping a leg. The shape of the location enablesthis. That is, when navigating down the page, the shape is expandingalong the dimension of the legs. However, when the UAV 632 executes aturn to move upward, the shape shrinks in the dimension, which providesfor greater room for the UAV 632 to complete the turn. Therefore, whenthe UAV 632 executes turn 640, the UAV 632 has more space to completethe turn, enabling the UAV 632 to reach the adjacent leg 642.

FIG. 6F illustrates examples transitions between example legs. In FIG.6F, a UAV has navigated along a last leg (e.g., a final leg, such as anextremity, border, of the area to be inspected, as labeled by ‘i’described above), and is navigating to a final leg to be inspectedaccording to a determined order (e.g., a final leg pass number). Thatis, as illustrated the UAV has navigating along a leg ordered as beingthe k^(th) leg to be navigated, and therefore is going to navigate alonga subsequent leg according to the order (e.g., k=k+1). Since the UAV, asillustrated, cannot navigate according to a radiator flight pattern, andtherefore cannot navigate from leg k to k=k+1 by making a simple turn(e.g., the minimum turning radius will not allow the UAV to execute theturn), the UAV has executed a maneuver to navigate along leg k=k+1. Forinstance, the UAV can execute a first turn (e.g., turn 652, according tothe UAV's minimum turning radius) to navigate up the area to beinspected (e.g., orthogonal to a direction of each leg), and thenexecute a second turn (e.g., turn 654) to navigate along k=k+1. In thisway, the UAV can navigate according to an order that it determines (e.g.as described above), or the system determines, and ensure that itnavigates along each leg.

Referring to FIG. 6G, the UAV or ground control station may receive aflight plan for a survey pattern to be conducted by a fixed-wing UAV.The flight plan may include five or more legs to be flown by the UAV toperform an inspection for a large survey area. The legs of the surveypattern are horizontally disposed from one another. The flight plan caninclude one or more multiple five-leg patterns, and can cause the UAV tofly to a position at a first altitude. The UAV can then proceed to afirst leg (Leg 1′) of the flight pattern, and fly in a first directionalong the first leg. Instead of banking to an adjacent leg, for exampleleg two (Leg 2′), which may require a steep banking angle, or a dog-bonepattern, the UAV can bank at a shallower angle proceeding to a fourthleg (Leg 4′), thereby skipping legs two and three. The UAV can navigatein a second direction opposite the first direction along the fourth leg.At the end of the fourth leg, the UAV can bank back towards the secondleg (Leg 2′), thereby skipping leg three (Leg 3′). The UAV can navigatealong the second leg in a similar direction of the first leg. At the endof the second leg, the UAV can bank towards a fifth leg (Leg 5′), andfly along the fifth leg in a similar direction as the fourth leg. At theend of the fifth leg, the UAV can bank towards the third leg, andnavigate along the third leg in a direction similar to the fifth leg. Atthe end of the third leg (Leg 3′), the UAV may continue with anotherfive leg pattern, and navigate to Leg 1″ of the next pattern which issimilar to the first five leg pattern, but the flight direction of thecorresponding legs are flown in the opposite direction. For example, Leg1′ and Leg 1″ are flown in opposite directions, and Leg 3′ and Leg 3″are flown in opposite directions. For a very large survey area thisfive-leg pattern may be repeated multiple times. This flight patternprovides an efficient way to cover a large area, and reduce the bankangle flown by a fixed-wing plane thereby reducing the risk of potentialstalling of the plane. The five-leg pattern as discussed above may beconnected to other flight patterns. Also, ideally if a rectangular areais being inspected, the pattern would be flown with the legs of thepattern running the longer length of the rectangular area.

The spacing of the legs can be a function of the coverage area, field ofview of an onboard sensor, such as a fixed camera. The second leg isdisposed between the first and the third legs, the third leg is disposedbetween the second and the fourth legs, and the fourth leg is disposedbetween the third and the fifth leg.

The description above, for instance with respect to FIGS. 5-6G,described a system determining a flight pattern, including an orderassigned to each leg. Optionally, the UAV receive information indicatingvalues of particular parameters, including one or more of the minimumturning radius and the width between legs, and the UAV can determine anorder assigned to each leg (e.g., while in flight). That is, the UAV candetermine a next leg to navigate along based on an identifier of thecurrent leg and the current leg pass number (e.g., as described above,the UAV can determine whether k_(current)≧i_(current)+1 is true).Utilizing information identifying a current direction of the UAV, anidentifier of the current leg, and the current leg pass number, the UAVcan determine a particular leg to next navigate along, including adirectionality of the navigation (e.g., opposite to a currentdirection).

FIG. 7 is a flowchart of an example process 700 for a UAV modifying aflight plan according to wind affecting the UAV. For convenience, theprocess 700 will be described as being performed by a UAV of one or moreprocessors (e.g., a UAV implementing the example UAV architecturedescribed in FIG. 8).

The UAV determines measurements associated with wind affecting the UAVwhile navigating according to a flight plan (block 702). As describedabove, as the UAV navigates along one or more legs, wind can cause theUAV to be unable to capture images with a field of view directly down tothe surface. For instance, the UAV may have to bank against a directionof the wind, which can cause a camera of the UAV to be oriented at anangle away from vertically down. Similarly, the UAV may have to crab,with its nose partially, or fully, in a direction of the wind, which canmodify an orientation of the camera. As an example of determining wind,the UAV can a difference between predicted motion of the UAV and realmotion as measured by one or more sensors (e.g., using one or more ofattitude information from an inertial measurement unit, altitudeinformation, GNSS coordinates, optionally in conjunction with one ormore aerodynamic models).

The UAV modifies its flight maneuvering when capturing an image (block704). As described above, the UAV captures images periodically whilenavigating along legs. To counter the effects of wind, the UAV cantemporarily adjust its flight characteristics when capturing an image,such that resulting images are not skewed or rotated as described above.

For instance, a threshold distance, or time, prior to capturing animage, the UAV can prepare for capturing the image. That is, the UAV candetermine that if the UAV modifies its flight characteristics, at atime, or location, of image capture, the UAV will be oriented properly(e.g., nose along a direction of the leg, not banking). As describedabove, the UAV can temporarily increase a particular aspect of astability controller, such as a derivative term, to provide quickadjustments to wind affecting the UAV, which can increase the UAV'sability to remain stable during image capture. Since an increase in thederivative term may result in the stability controller becoming unstable(e.g., due to a buildup of the effects of the modification), aftertaking the image the UAV can modify the stability controller (e.g., backto a normal level).

Furthermore, the UAV can monitor measurements associated with wind, anddetermine a range of values associated with the measurements. Forinstance, the UAV can determine that the wind speed varies from aparticular value, to another particular value. As the UAV is approachinga location, or time, at which to capture an image, the UAV can capturethe image (e.g., and modify flight maneuvers) when the measurementsassociated with the wind are within a threshold level of the lowestaverage levels measured. Optionally, the flight plan being implementedcan include successive images that include overlap between each image.In this way, the UAV can have a range of locations, or times, at whichto capture an image, and can select a location, or time, within therange, such that a successive image can be captured and no area of thelocation will be missed in images. Optionally, if no lull in the wind isdetermined, the UAV can capture an image within the range.

After capturing an image, the UAV returns to the flight pattern andresumes countering the wind (block 706). After the image is captured,the UAV modifies its flight maneuvering to return to banking, crabbing,and so on, along the leg.

FIG. 8 illustrates a block diagram of an example Unmanned Aerial Vehicle(UAV) architecture for implementing the features and processes describedherein. A UAV primary processing system 800 can be a system of one ormore computers, or software executing on a system of one or morecomputers, which is in communication with, or maintains, one or moredatabases. The UAV primary processing system 800 can be a system of oneor more processors 835, graphics processors 836, I/O subsystem 834,logic circuits, analog circuits, associated volatile and/or non-volatilememory, associated input/output data ports, power ports, etc., and/orone or more software processing executing one or more processors orcomputers. Memory 818 may include non-volatile memory, such as one ormore magnetic disk storage devices, solid state hard drives, or flashmemory. Other volatile memory such a RAM, DRAM, SRAM may be used fortemporary storage of data while the UAV is operational. Databases maystore information describing UAV flight operations, flight plans,contingency events, geofence information, component information, andother information.

The UAV processing system may be coupled to one or more sensors, such asGPS receivers 850, gyroscopes 856, accelerometers 858, pressure sensors(static or differential) 852, current sensors, voltage sensors,magnetometer, hydrometer, and motor sensors. The UAV may use an inertialmeasurement unit (IMU) 832 for use in navigation of the UAV. Sensors canbe coupled to the processing system, or to controller boards coupled tothe UAV processing system. One or more communication buses, such as aCAN bus, or signal lines, may couple the various sensor and components.

Various sensors, devices, firmware and other systems may beinterconnected to support multiple functions and operations of the UAV.For example, the UAV primary processing system 800 may use varioussensors to determine the vehicle's current geo-spatial location,attitude, altitude, velocity, direction, pitch, roll, yaw and/orairspeed and to pilot the vehicle along a specified route and/or to aspecified location and/or to control the vehicle's attitude, velocity,altitude, and/or airspeed (optionally even when not navigating thevehicle along a specific path or to a specific location).

The flight control module 822 handles flight control operations of theUAV. The module interacts with one or more controllers 840 that controloperation of motors 842 and/or actuators 844. For example, the motorsmay be used for rotation of propellers, and the actuators may be usedfor flight surface control such as ailerons, rudders, flaps, landinggear, and parachute deployment.

The contingency module 824 monitors and handles contingency events. Forexample, the contingency module may detect that the UAV has crossed aborder of a geofence, and then instruct the flight control module toreturn to a predetermined landing location. Other contingency criteriamay be the detection of a low battery or fuel state, or malfunctioningof an onboard sensor, motor, or a deviation from the flight plan. Theforegoing is not meant to be limiting, as other contingency events maybe detected. In some instances, if equipped on the UAV, a parachute maybe deployed if the motors or actuators fail.

The mission module 829 processes the flight plan, waypoints, and otherassociated information with the flight plan as provided to the UAV inthe flight package. The mission module 829 works in conjunction with theflight control module. For example, the mission module may sendinformation concerning the flight plan to the flight control module, forexample lat/long waypoints, altitude, flight velocity, so that theflight control module can autopilot the UAV.

The UAV may have various devices connected to it for data collection.For example, photographic camera 849, video cameras, infra-red camera,multispectral camera, and Lidar, radio transceiver, sonar, TCAS (trafficcollision avoidance system). Data collected by the devices may be storedon the device collecting the data, or the data may be stored onnon-volatile memory 818 of the UAV processing system 800.

The UAV processing system 800 may be coupled to various radios, andtransmitters 859 for manual control of the UAV, and for wireless orwired data transmission to and from the UAV primary processing system800, and optionally the UAV secondary processing system 802. The UAV mayuse one or more communications subsystems, such as a wirelesscommunication or wired subsystem, to facilitate communication to andfrom the UAV. Wireless communication subsystems may include radiotransceivers, and infrared, optical ultrasonic, electromagnetic devices.Wired communication systems may include ports such as Ethernet, USBports, serial ports, or other types of port to establish a wiredconnection to the UAV with other devices, such as a ground controlsystem, flight planning system, or other devices, for example a mobilephone, tablet, personal computer, display monitor, other othernetwork-enabled devices. The UAV may use a light-weight tethered wire toa ground control station for communication with the UAV. The tetheredwire may be removeably affixed to the UAV, for example via a magneticcoupler.

Flight data logs may be generated by reading various information fromthe UAV sensors and operating system and storing the information innon-volatile memory. The data logs may include a combination of variousdata, such as time, altitude, heading, ambient temperature, processortemperatures, pressure, battery level, fuel level, absolute or relativeposition, GPS coordinates, pitch, roll, yaw, ground speed, humiditylevel, velocity, acceleration, contingency information. This foregoingis not meant to be limiting, and other data may be captured and storedin the flight data logs. The flight data logs may be stored on aremovable media and the media installed onto the ground control system.Alternatively, the data logs may be wirelessly transmitted to the groundcontrol system or to the flight planning system.

Modules, programs or instructions for performing flight operations,contingency maneuvers, and other functions may be performed with theoperating system. In some implementations, the operating system 120 canbe a real time operating system (RTOS), UNIX, LINUX, OS X, WINDOWS,ANDROID or other operating system. Additionally, other software modulesand applications may run on the operating system, such as a flightcontrol module 822, contingency module 824, application module 826, anddatabase module 828. Typically flight critical functions will beperformed using the UAV processing system 800. Operating system 820 mayinclude instructions for handling basic system services and forperforming hardware dependent tasks.

In addition to the UAV primary processing system 800, a secondaryprocessing system 802 may be used to run another operating system toperform other functions. A UAV secondary processing system 802 can be asystem of one or more computers, or software executing on a system ofone or more computers, which is in communication with, or maintains, oneor more databases. The UAV secondary processing system 802 can be asystem of one or more processors 894, graphics processors 892, I/Osubsystem 894 logic circuits, analog circuits, associated volatileand/or non-volatile memory, associated input/output data ports, powerports, etc., and/or one or more software processing executing one ormore processors or computers. Memory 870 may include non-volatilememory, such as one or more magnetic disk storage devices, solid statehard drives, flash memory. Other volatile memory such a RAM, DRAM, SRAMmay be used for storage of data while the UAV is operational.

Ideally modules, applications and other functions running on thesecondary processing system 802 will be non-critical functions innature, that is if the function fails, the UAV will still be able tosafely operate. In some implementations, the operating system 872 can bebased on real time operating system (RTOS), UNIX, LINUX, OS X, WINDOWS,ANDROID or other operating system. Additionally, other software modulesand applications may run on the operating system 872, such as anapplication module 874, database module 876. Operating system 802 mayinclude instructions for handling basic system services and forperforming hardware dependent tasks.

Also, controllers 846 may be used to interact and operate a payloaddevice 848, and other devices such as photographic camera 849, videocamera, infra-red camera, multispectral camera, stereo camera pair,Lidar, radio transceiver, sonar, laser ranger, altimeter, TCAS (trafficcollision avoidance system), ADS-B (Automatic dependentsurveillance—broadcast) transponder. Optionally, the secondaryprocessing system 802 may have coupled controllers to control payloaddevices.

Each of the processes, methods, instructions, applications andalgorithms described in the preceding sections may be embodied in, andfully or partially automated by, code modules executed by one or morecomputer systems or computer processors comprising computer hardware.The code modules (or “engines”) may be stored on any type ofnon-transitory computer-readable medium or computer storage device, suchas hard drives, solid state memory, optical disc, and/or the like. Thesystems and modules may also be transmitted as generated data signals(for example, as part of a carrier wave or other analog or digitalpropagated signal) on a variety of computer-readable transmissionmediums, including wireless-based and wired/cable-based mediums, and maytake a variety of forms (for example, as part of a single or multiplexedanalog signal, or as multiple discrete digital packets or frames). Theprocesses and algorithms may be implemented partially or wholly inapplication-specific circuitry. The results of the disclosed processesand process steps may be stored, persistently or otherwise, in any typeof non-transitory computer storage such as, for example, volatile ornon-volatile storage.

User interfaces described herein are optionally presented (and userinstructions may be received) via a user computing device using abrowser, other network resource viewer, a dedicated application, orotherwise. Various features described or illustrated as being present indifferent embodiments or user interfaces may be combined into the sameembodiment or user interface. Commands and information received from theuser may be stored and acted on by the various systems disclosed hereinusing the processes disclosed herein. While the disclosure may referenceto a user hovering over, pointing at, or clicking on a particular item,other techniques may be used to detect an item of user interest. Forexample, the user may touch the item via a touch screen, or otherwiseindicate an interest. The user interfaces described herein may bepresented on a user terminal, such as a laptop computer, desktopcomputer, tablet computer, smart phone, virtual reality headset,augmented reality headset, or other terminal type. The user terminalsmay be associated with user input devices, such as touch screens,microphones, touch pads, keyboards, mice, styluses, cameras, etc. Whilethe foregoing discussion and figures may illustrate various types ofmenus, other types of menus may be used. For example, menus may beprovided via a drop down menu, a tool bar, a pop up menu, interactivevoice response system, or otherwise.

In general, the terms “engine” and “module”, as used herein, refer tologic embodied in hardware or firmware, or to a collection of softwareinstructions, possibly having entry and exit points, written in aprogramming language, such as, for example, Java, Lua, C or C++. Asoftware module may be compiled and linked into an executable program,installed in a dynamic link library, or may be written in an interpretedprogramming language such as, for example, BASIC, Perl, or Python. Itwill be appreciated that software modules may be callable from othermodules or from themselves, and/or may be invoked in response todetected events or interrupts. Software modules configured for executionon computing devices may be provided on a computer readable medium, suchas a compact disc, digital video disc, flash drive, or any othertangible medium. Such software code may be stored, partially or fully,on a memory device of the executing computing device. Softwareinstructions may be embedded in firmware, such as an EPROM. It will befurther appreciated that hardware modules may be comprised of connectedlogic units, such as gates and flip-flops, and/or may be comprised ofprogrammable units, such as programmable gate arrays or processors. Themodules described herein are preferably implemented as software modules,but may be represented in hardware or firmware. Generally, the modulesdescribed herein refer to logical modules that may be combined withother modules or divided into sub-modules despite their physicalorganization or storage. Electronic data sources can include databases,volatile/non-volatile memory, and any memory system or subsystem thatmaintains information.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure. In addition, certain method or processblocks may be omitted in some implementations. The methods and processesdescribed herein are also not limited to any particular sequence, andthe blocks or states relating thereto can be performed in othersequences that are appropriate. For example, described blocks or statesmay be performed in an order other than that specifically disclosed, ormultiple blocks or states may be combined in a single block or state.The example blocks or states may be performed in serial, in parallel, orin some other manner. Blocks or states may be added to or removed fromthe disclosed example embodiments. The example systems and componentsdescribed herein may be configured differently than described. Forexample, elements may be added to, removed from, or rearranged comparedto the disclosed example embodiments.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “for example,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations, and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list. Conjunctivelanguage such as the phrase “at least one of X, Y and Z,” unlessspecifically stated otherwise, is otherwise understood with the contextas used in general to convey that an item, term, etc. may be either X, Yor Z. Thus, such conjunctive language is not generally intended to implythat certain embodiments require at least one of X, at least one of Yand at least one of Z to each be present.

The term “a” as used herein should be given an inclusive rather thanexclusive interpretation. For example, unless specifically noted, theterm “a” should not be understood to mean “exactly one” or “one and onlyone”; instead, the term “a” means “one or more” or “at least one,”whether used in the claims or elsewhere in the specification andregardless of uses of quantifiers such as “at least one,” “one or more,”or “a plurality” elsewhere in the claims or specification.

The term “comprising” as used herein should be given an inclusive ratherthan exclusive interpretation. For example, a general purpose computercomprising one or more processors should not be interpreted as excludingother computer components, and may possibly include such components asmemory, input/output devices, and/or network interfaces, among others.

While certain example embodiments have been described, these embodimentshave been presented by way of example only, and are not intended tolimit the scope of the disclosure. Nothing in the description isintended to imply that any particular element, feature, characteristic,step, module, or block is necessary or indispensable. The novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions, and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the inventions disclosed herein. Theaccompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit ofcertain of the inventions disclosed herein.

Any process descriptions, elements, or blocks in the flow diagramsdescribed herein and/or depicted in the attached figures should beunderstood as potentially representing modules, segments, or portions ofcode which include one or more executable instructions for implementingspecific logical functions or steps in the process. Alternateimplementations are included within the scope of the embodimentsdescribed herein in which elements or functions may be deleted, executedout of order from that shown or discussed, including substantiallyconcurrently or in reverse order, depending on the functionalityinvolved, as would be understood by those skilled in the art.

It should be emphasized that many variations and modifications may bemade to the to the above-described embodiments, the elements of whichare to be understood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of the disclosure. The foregoing description details certainembodiments of the invention. It will be appreciated, however, that nomatter how detailed the foregoing appears in text, the invention can bepracticed in many ways. As is also stated above, it should be noted thatthe use of particular terminology when describing certain features oraspects of the invention should not be taken to imply that theterminology is being re-defined herein to be restricted to including anyspecific characteristics of the features or aspects of the inventionwith which that terminology is associated.

What is claimed is:
 1. An unmanned aerial vehicle (UAV) system comprising one or more processors comprising hardware, the one or more processors configured to perform operations comprising: determining a boundary for an area to be inspected by an unmanned aerial vehicle (UAV); determining a flight pattern for the area, the flight pattern including a plurality of inspection legs being substantially parallel to one another, and adjacent inspection legs being separated, by a particular width, wherein at least a first set of two adjacent inspection legs are to be traversed in the same direction by the UAV, wherein each inspection leg is associated with the UAV performing an aerial inspection of the area along the inspection leg; and autonomously navigating the UAV according to the determined flight pattern, and obtaining sensor data of the area while the UAV navigates along each inspection leg.
 2. The system of claim 1, the operations further comprising: selecting a particular UAV to perform an inspection for the area; and determining the navigation order of each inspection leg based on a turning radius associated with the selected UAV.
 3. The system of claim 1, the operations further comprising: determining measurements associated with wind affecting the flight of the UAV; based on the determined measurements, modifying flight maneuvering of the UAV to change the orientation of the UAV, and capturing a digital image; and after capturing the digital image, returning the UAV to the path of the then current inspection leg.
 4. The system of claim 1, the operations further comprising: determining a navigation order for each inspection leg.
 5. The system of claim 1, wherein the flight pattern includes a plurality of curved sections connecting the respective inspection legs, the sections constrained by a minimum turning radius of the UAV used for the inspection.
 6. The system of claim 1, the operations further comprising: navigating the UAV along a first inspection leg in a first direction to an end of the first inspection leg; navigating the UAV to a third inspection leg, the third inspection leg being non-adjacent to the first inspection leg; navigating the UAV in a second direction opposite the first direction along the third inspection leg and to an end of the third inspection leg; and navigating the UAV to the second inspection leg, and navigating the UAV along the second inspection leg and to an end of the second inspection leg in the same direction as the first direction.
 7. The system of claim 1, wherein determining a flight pattern comprises: a first inspection leg for navigation by the UAV to be flown in a first direction along the first inspection leg; a curved segment at the end of the first inspection leg connecting the first inspection leg to a fourth inspection leg, the fourth leg to be flown in a second direction opposite the first direction; a curved segment at the end of the forth inspection leg connecting the fourth inspection leg to a second inspection leg, the second inspection leg to be flown in the first direction; a curved segment at the end of the second inspection leg connecting the second inspection leg to a fifth inspection leg, the fifth inspection leg to be flow in the second direction; and a curved segment at the end of the fifth inspection leg connecting the fifth inspection leg to a third inspection leg, the third inspection leg to be flow in the first direction; wherein the second inspection leg is disposed between the first and the third inspection legs, the third inspection leg is disposed between the second and the fourth inspection legs, and the fourth inspection leg is disposed between the third and the fifth inspection legs.
 8. The system of claim 1, wherein the flight pattern further comprises at least a second set of two adjacent inspection legs that are to be traversed in an opposite direction than the first set.
 9. The system of claim 1, wherein the flight pattern includes the UAV performing from a take-off location a flight to an enroute spiral to orient the UAV along a direction of an initial leg of the flight pattern.
 10. The system of claim 1, the operations further comprising: determining the particular width between inspection legs based on configuration information of the UAV, and a ground sampling distance for images to be obtained by the UAV.
 11. A non-transitory computer storage medium comprising instructions that when executed by an unmanned aerial vehicle (UAV) system comprising one or more processors, cause the one or more processors to perform operations comprising: determining a boundary for an area to be inspected by an unmanned aerial vehicle (UAV); determining a flight pattern for the area, the flight pattern including a plurality of inspection legs being substantially parallel to one another, and adjacent inspection legs being separated, by a particular width, wherein at least a first set of two adjacent inspection legs are to be traversed in the same direction by the UAV, wherein each inspection leg is associated with the UAV performing an aerial inspection of the area along the inspection leg; and autonomously navigating the UAV according to the determined flight pattern, and obtaining sensor data of the area while the UAV navigates along each inspection leg.
 12. The non-transitory computer storage medium of claim 11, the operations further comprising: selecting a particular UAV to perform an inspection for the area; and determining the navigation order of each inspection leg based on a turning radius associated with the selected UAV.
 13. The non-transitory computer storage medium of claim 11, the operations further comprising: determining measurements associated with wind affecting the flight of the UAV; based on the determined measurements, modifying flight maneuvering of the UAV to change the orientation of the UAV, and capturing a digital image; and after capturing the digital image, returning the UAV to the path of the then current inspection leg.
 14. The non-transitory computer storage medium of claim 11, the operations further comprising: determining a navigation order for each inspection leg.
 15. The non-transitory computer storage medium of claim 11, wherein the flight pattern includes a plurality of curved sections connecting the respective inspection legs, the sections constrained by a minimum turning radius of the UAV used for the inspection.
 16. The non-transitory computer storage medium of claim 11, the operations further comprising: navigating the UAV along a first inspection leg in a first direction to an end of the first inspection leg; navigating the UAV to a third inspection leg, the third inspection leg being non-adjacent to the first inspection leg; navigating the UAV in a second direction opposite the first direction along the third inspection leg and to an end of the third inspection leg; and navigating the UAV to the second inspection leg, and navigating the UAV along the second inspection leg and to an end of the second inspection leg in the same direction as the first direction.
 17. The non-transitory computer storage medium of claim 11, wherein determining a flight pattern comprises: a first inspection leg for navigation by the UAV to be flown in a first direction along the first inspection leg; a curved segment at the end of the first inspection leg connecting the first inspection leg to a fourth inspection leg, the fourth leg to be flown in a second direction opposite the first direction; a curved segment at the end of the forth inspection leg connecting the fourth inspection leg to a second inspection leg, the second inspection leg to be flown in the first direction; a curved segment at the end of the second inspection leg connecting the second inspection leg to a fifth inspection leg, the fifth inspection leg to be flow in the second direction; and a curved segment at the end of the fifth inspection leg connecting the fifth inspection leg to a third inspection leg, the third inspection leg to be flow in the first direction; wherein the second inspection leg is disposed between the first and the third inspection legs, the third inspection leg is disposed between the second and the fourth inspection legs, and the fourth inspection leg is disposed between the third and the fifth inspection legs.
 18. The non-transitory computer storage medium of claim 11, wherein the flight pattern further comprises at least a second set of two adjacent inspection legs that are to be traversed in an opposite direction than the first set.
 19. The non-transitory computer storage medium of claim 11, wherein the flight pattern includes the UAV performing from a take-off location a flight to an enroute spiral to orient the UAV along a direction of an initial leg of the flight pattern.
 20. The non-transitory computer storage medium of claim 11, the operations further comprising: determining the particular width between inspection legs based on configuration information of the UAV, and a ground sampling distance for images to be obtained by the UAV.
 21. A computerized method performed by an unmanned aerial vehicle (UAV) system comprising one or more processors, the method comprising: determining a boundary for an area to be inspected by an unmanned aerial vehicle (UAV); determining a flight pattern for the area, the flight pattern including a plurality of inspection legs being substantially parallel to one another, and adjacent inspection legs being separated, by a particular width, wherein at least a first set of two adjacent inspection legs are to be traversed in the same direction by the UAV, wherein each inspection leg is associated with the UAV performing an aerial inspection of the area along the inspection leg; and autonomously navigating the UAV according to the determined flight pattern, and obtaining sensor data of the area while the UAV navigates along each inspection leg.
 22. The method of claim 21, further comprising: selecting a particular UAV to perform an inspection for the area; and determining the navigation order of each inspection leg based on a turning radius associated with the selected UAV.
 23. The method of claim 21, further comprising: determining measurements associated with wind affecting the flight of the UAV; based on the determined measurements, modifying flight maneuvering of the UAV to change the orientation of the UAV, and capturing a digital image; and after capturing the digital image, returning the UAV to the path of the then current inspection leg.
 24. The method of claim 21, further comprising: determining a navigation order for each inspection leg.
 25. The method of claim 21, wherein the flight pattern includes a plurality of curved sections connecting the respective inspection legs, the sections constrained by a minimum turning radius of the UAV used for the inspection.
 26. The method of claim 21, further comprising: navigating the UAV along a first inspection leg in a first direction to an end of the first inspection leg; navigating the UAV to a third inspection leg, the third inspection leg being non-adjacent to the first inspection leg; navigating the UAV in a second direction opposite the first direction along the third inspection leg and to an end of the third inspection leg; and navigating the UAV to the second inspection leg, and navigating the UAV along the second inspection leg and to an end of the second inspection leg in the same direction as the first direction.
 27. The method of claim 2, wherein the flight pattern comprises: a first inspection leg for navigation by the UAV to be flown in a first direction along the first inspection leg; a curved segment at the end of the first inspection leg connecting the first inspection leg to a fourth inspection leg, the fourth leg to be flown in a second direction opposite the first direction; a curved segment at the end of the forth inspection leg connecting the fourth inspection leg to a second inspection leg, the second inspection leg to be flown in the first direction; a curved segment at the end of the second inspection leg connecting the second inspection leg to a fifth inspection leg, the fifth inspection leg to be flow in the second direction; and a curved segment at the end of the fifth inspection leg connecting the fifth inspection leg to a third inspection leg, the third inspection leg to be flow in the first direction; wherein the second inspection leg is disposed between the first and the third inspection legs, the third inspection leg is disposed between the second and the fourth inspection legs, and the fourth inspection leg is disposed between the third and the fifth inspection legs.
 28. The method of claim 21, wherein the flight pattern includes at least a second set of two adjacent inspection legs that are to be traversed in an opposite direction than the first set.
 29. The method of claim 21, wherein the flight pattern includes the UAV performing from a take-off location a flight to an enroute spiral to orient the UAV along a direction of an initial leg of the flight pattern.
 30. The method of claim 21, the further comprising: determining the particular width between inspection legs based on configuration information of the UAV, and a ground sampling distance for images to be obtained by the UAV. 